Are there any good tutorials for someone who wants to create 2D graphical game assets? Drawing classes for absolute beginners, preferably teaching skills that can be as relevant as possible to games - drawing characters sideways/top-down, isometric, drawing textures and such.
First, you want to search for tutorials on the internet. Youtube is your friend. Seriously, it's probably the best way to learn drawing. It's easy to look at some really amazing drawing and say "oh, I could never do that, he's been doing that since he was a kid." But when someone slowly walks you through the steps and explains every part of the way, the mountain suddenly seems a lot easier to climb.
Next the problem is figuring out what to search for. You don't want to start off with the hard stuff, so don't go searching for "digital art" or "character design" as you will be lost very fast. There's a lot of tutorials out there that start off like "first draw a basic human figure" or "start by sketching out some buildings". Avoid those.
Now, a tutorial to get you started. First, search YouTube for "perspective drawing". It's a basic skill that's the first thing they teach you in any art class. Play around with this a bit, drawing 3D houses, etc. Now, try to find something in your house that's roughly box-shaped. Your speakers or desktop should work fine. Now draw it using perspective. What you just did is called "life drawing" which is basically where you draw something from real life. It's really important that you do this, because you figure out neat little things on your own when you draw real things.
Also, when you watch a tutorial you'll see that a lot of what you drew looks a lot messier or uglier than what you saw in the tutorial. Do not be worried, it's not that you're less creative or that you didn't follow the tutorial, you just haven't built up some of the basic skills that the artists in the tutorials have. An easy way to help this is to just draw lots of basic shapes over and over again. Keep a pad of paper next to you while watching tv, and during the commercial break see if you can draw 20 circles, lines, or squares. Think of it like learning the basic methods in a new language so that you don't have to look through pages of the documentation.
Another thing to watch out for is details. Say you're drawing a person. You decide to start with the head. So you start with drawing a circle. Then you think "oh, I've already got the circle, I'll give it eyes and a mouth!" Next thing you know, you've got a pretty good head, with hair, a nose, eyes, a mouth, ears, etc. So you start drawing the body. After doing some pretty good shoes and maybe a cool shoulder armor you realize that your drawing looks horrible. The head is too big, the legs are different sizes, and the feet look backwards. My point is that you have to focus on big shapes and try to resist the urge to start adding details.
Finally, learn to critique your own drawings. Don't just look at the person you drew and say "that's ugly". Pick out specific things to improve upon. Say "those hands could be better" or "the proportions seem kinda weird" or "The hair looks too fuzzy". Then look up tutorials for whatever you need to improve on. There's a lot of good resources out there, but you have to know what you are looking for. You wouldn't just search for "Making my program faster", you would look up "improving performance rendering triangle strips in XNA".
Anyways, assuming you already did perspective drawing, here's some things to search for to get stated. (inserting "tutorial" after all of these can give better results) 3D shading Figure drawing Gesture drawing Basic Pixel Art
Just with that stuff you should have a good month or two of stuff to practice. Try to keep sketchbooks, so that you can look back and see how much you've improved. If you want to look forward and see how good you can get, look up "speed painting" on YouTube. And if you are getting frustrated with all sorts of technical details and stuff, watch this video and try to have some fun.
Good luck, and make sure you draw often!
As a fellow programmer who has just recently begun to get a handle on hand-drawn art, I'll give you my 2 cents:
Note: I'm going to assume you mostly want to create characters and sets. IF not, ignore this answer :P
So, first off, you'll want to know some basic anatomy. Know the proportion of each major part of the body (torso, neck, head, hands, upper and lower of limbs, etc). You'll want to know how each joint connects and it's axis and angles of rotation. And you'll want a basic idea of how the muscle groups work both relaxed and in flexion.
Secondly, you need to know to compare your work with one of a similar stage of production. By that I mean, if you're drawing in pencil, compare it to pencil sketches, not to an inked and coloured image (in order of production: Pencil -> Ink -> Colour -> Composition).
Finally, the tools maketh the man. That's not to say that you can't be an artist without spending big money on pencils and brushes, but just understand that you'll struggle to get a decent drawing using just a pacer. Learning when to us different weights of pencil/brush are as important as knowing how to draw the lines.
The process of learning a particular form of art can be greatly accelerated by following a 3 stage process: Copy, Modify, Create
Find an artist whose style you like, and just try tracing their artwork. What you should be aiming to do here is to get a feel for differences in aspects of the drawing such as smooth versus angular angle/curves, heavy/light lines, proportion, etc.
Now, take one of their drawings, and modify it in some way. What you're doing here is trying to imitate their art style, using an existing piece as a template. As always, start with a small change (maybe change the pose of a hand, or the tilt of their head), then work up to a bigger change (change the pose of an entire leg, or arm), then finally a complete body pose.
So, by this stage, you can take an existing artwork, and draw it in a new pose. Now, start from scratch. Take an existing character, and with no exact reference, draw them from scratch.
I would take the important facts from people who say it's too late, but also ignore them. When I started making games I wasn't very good at drawing, but still managed to learn what I needed. I'm never going to make the final graphics for any of my games in reality, but I learned enough to prototype my idea to the designers that I work with. This way you can still keep your "tone" and have someone who knows what their doing do the heavy lifting. I'de say my artist partner and music partners are the reason I got past the old days of having a cool game idea in very basic playable form. Actually the first game I ever finished was the first project I had the partners on.
That said, knowing how to prototype your art to keep your vision is very important if you have your own ideas.
I'de say 3dbuzz and lynda are the most helpful resources for me as far as art in general goes. I spent about 200 hours on these sites and can get my ideas across to designers very well now. I still will never publish my art, real designers can do this stuff effortlessly.
Really short answer, given that I just wrote a longer one over here: The Natural Way to Draw, by Kimon Nicolaïdes, is a great book that also contains a study plan. Another good book is Harold Speed's "The practice & science of drawing".