Ya right!!! They don't have the time/skill to do their own software?
You need to spend some time on game-dev forums and sites.
First off, game companies OFTEN develope their own software to do their work, because each company has very specific needs, and also because new games tend to use new technologies that haven't been out before, so they have to develope interfaces and the tools themselves.
Epic and LEGEND, for instance, use their own modeling and 3D-graphics mapping software, in the development of all the UT games, not to mention their other games.
Maya is not universally used.
The most popular commercially-available 3D-modeling apps are Maya, 3Dstudio, Bryce, and Lightwave.
Often, however, gaming companies use highly modified versions of these software packages to more-or-less create their own modeling environments.
All you really need to do to get into the gaming industry, is know HOW to model REALLY REALLY REALLY REALLY well. I mean, like, you can model in your sleep, upside-down, on a twelve-day hangover, with about 2 hours sleep, with a pair of nerds having a mock lightsabre battle through your cubical, with your boss in the cell in your ear from London...and create something stunning in the alotted time.
Gaming companies don't really care what app you've used (as long as it's not old as dirt and you have some experience with at least the newest technologies in modeling of this year). They can train you for their own software, and knowing how to model you should be able to jump from one app to the next without too much difficulty.
All they'll want from you is a big stack portfolio of modeling work, including a wide-range of "industry" forms, and a clear grasp of the basic and intermediate technologies. They will also be looking for someone who has experience with the newest technologies, and especially someone who can do it!
If you're young (up to just starting college), I would seriously suggest completing a very rich liberal-arts degree, getting as much knowledge as you can about as much stuff as you can. Game companies CRAVE people who have extensive historical, art, engineering, and social skills. This is so when they say "hey guys, we're making an Egyptian style map," they'll have mappers and modelers who know what the hell Egypt is and what kinds of details would go into an Egyptian level to make it Egyptian-y. (How would a mapper/modeler know how to create the islands of FarCry if he/she had never been on an island before?)
Once you get done with that (and I hope to god you spent all your off time teaching yourself modeling and mapping and maybe did some interning and forum work) you should attend a gaming college. Yes, one of those little schools in the middle of nowhere, where they teach the gaming industry. (FullSail is a notable one.)
As for the textures used in creating games, there's two kinds. Model textures, and flat textures.
Flat textures are the kind used for walls and floors and stuff like that. All the geometry textures. They're created in just about any graphics application you can get your hands on, because the only real requirements for them are number-of-colors, and size (in pixels). Most games have an internal graphics engine that has its own format created by the developers (such as Half-Life, UT, WC, MoH, etc). You can have a JPEG or a BMP, but when you import them into the game, they get converted to another internal standard.
3D textures are those intended for use on models (particularly figure models. Developing images for this can be tricky, as you can take a flat picture of a person and just wrap it onto a figure model and make it look right. It won't work. Usually models are created with special graphics apps along-side, or by "painting" directly on the model. Once you get the hang of it, you can literally take a line-map from the feature (say, the face) of a model, export it out to a flat image (now distorted since it's not curved anymore) and paint on it. You have to have a good eye for this and know how things will work when you put it back on the model.
If you want to learn how flat-textures work, I would seriously check out Half-Life's graphics engine. Get Wally, a great too for making Quake and Half-Life textures. Doing some mapping with Half-Life's Hammer editor will teach you all you need to know about flat-texturing.
For learning about 3D-texturing, and how those work, I would suggest pulling out an app called UPaint, which is distributed with UT games. It's a model texture editor that allows you to change the textures of the models in the game. You can export the graphics off the characters, mod them, and put them back on. Doing this, you'll see exactly how 3D-textures differ from flat-textures.
Okay, I'm done (for now).