I also know http://ffdmag.com/ ,there's texts about flash (sometimes related to games)
Besides Game Developer Magazine from UBN TechWeb and Develop from Intent Media, you could find a game developer magazine in DEVMAG. This website is not frequently updated comparing with the first two but it provides free archived PDFs to read and you could reach issue 1 to 29.
Gamasutra is the online companion to Game Developer Magazine, both are UBM TechWeb publications but for whatever reason, the original online content and reprints go to Gamasutra.com, while the gdmag.com website basically just serves as an online table of contents for the current print issue.
As far as I know Game Developer Magazine is the only print magazine that targets game developers specifically, although there are a few additional online resources like GamesIndustry.biz and GameDev.net, which is a great site with a bit more of an indy/hobbyist bent but definitely a great resource with plenty of participants from industry.
There is also Develop, at develop-online.net .
AltDevBlogADay is also sometimes interesting.
There is indiegamemag as well
There's also Big Bytes and Small Nibbles
It contains a mix of reviews, design-focused interviews, and the occasional essay on an aspect of game design.