You question, as already mentioned, is quite broad and can easily be interpreted in multiple ways. One important requirement is why you want to create an FPS game, your. Your objective is important in narrowing down how to can achieve your goal. Are you just testing the water, perhaps to do bigger things, or is this just an interest and not necessarily some kind of career opportunity. Or are you just not sure?
The FPS game genre is quite old and as a result there are multiple ways in which you can create FPS type games depending on what you want to do. Here are just a few game engines that may be of interest to you:
Unreal Development Kit (Free for Non-commercial use)
Unity (Gaining serious popularity, free version available)
CryENGINE 3 (http://mycryengine.com/)
Unreal Development Kit (free for non-commercial use)
Unity (gaining serious popularity, free version available)
For a much more comprehensive list look here: http://www.indiedb.com/engineslook here.
At the other end of the spectrum are game engines designed for complete novices like these ones:
FPS Creator (Very popular and easy to use but laggy at times requires no coding, http://www.thegamecreators.com/
Silent Walk FPS Creator and Silent Walk: Renaissance(FREE) Both designed for complete novices and both require no programming and can be used to create FPS in a very short time, but lack modern effects.
(Google them for more info)
FPS Creator (very popular and easy to use but slow at times; requires no coding)
Silent Walk FPS Creator and Silent Walk: Renaissance; both designed for complete novices and both require no programming and can be used to create FPS in a very short time, but lack modern effects.
As for software and modelling tools you will need to try them out for yourself to get the 'feel' for them, but to make you job a little easier I have compiled a page which lists a number of thema page which lists a number of them, I have only focused on listing free programs that can be used in game creation only though. http://freegameslist.weebly.com/game-creation-tools.html