Ok, before I try anythig and mess something up, can you use the G.E.C.K. for the PS3 Fallout New Vegas? or does it only allow it on the computer? Thank you for any help!

PC only, how on earth did you expect to use actual game design software on a console?

*sigh* This falls under the category of common sense.

The GECK is for PC platforms, can't mod the PS3 or Xbox without violating EULA or warranty or whatever. Sorry.