viv files are like the iff files in 2K, except you can extract their parts and put them directly in the sgsm folder and they will be loaded by the game (so you dont need to reimport stuff into them). Dolphin, bigGUI, or EAgraph to import/extract/create viv files.
fsh files are textures, there can be multiple textures in 1 fsh file. Dolphin claims to be able to edit them, but eh. fshx is preferred.
ebo files are models, use ebo editor (v1) or ebodit (v2) to edit. Neither are any good in comparison to Blender tbh.
Rosters are dbf files, just open them in openoffice or excel or dbcommander and go nuts. No licenses or any crap like that here.
lit5on5.urb is the lighting file, editable with notepad. its bitchin.
pretty much it, all the tools are in the downloads section
downloads.php?cat=1 and lots of tutorials in each subforum and wiki
http://www.nba-live.com/nbalivewiki/index.php/Main_Page (wiki is better)
best of luck