You can rip files from a video game disc directly to your computer, but it's a little tricky. I've only ever done it with Gamecube and Wii games. You need special software, and it only works with certain disc drives; all of which were made around the year 2002. The disc drives that work for ripping Nintendo games aren't the same ones that work for ripping Xbox games though.
I'm not sure that you'd need a special disc drive for ripping Xbox games, but I don't know much about it. I just found this program that claims it can rip files from Xbox 360 discs, without needing a special disc drive. If it works with Xbox 360 discs, it probably also works with Xbox discs.
I don't know much about ripping video game discs using the system itself, so that might be easier. If it isn't though, here's a link to a website that has information about and instructions on how to use the program that I found. It's free software and there's a link to download it right there. The program is called wxRipper.
http://www.ps3hax.net/showthread.php?t=9165The developers are probably planning to convert all of the THPS2X levels from THPS3 LevelMod anyways. If you want to help out with the game, you should contact them first.