Remember playing with LEGO as a youth? You can again!
Download the tools at www.ldraw.org (I suggest the full install which weighs in at around 35mb, but includes everything) and get to crackin. If you want instructions for building models, check out www.brickshelf.com - you can search by model # or browse images to find what you want. I already made a cheapo spaceship and am now going to start work on one of the big ass ships I could never afford as a youngin.
Anyway, let's see how creative the TNL people are!
http://www.versuscity.net/crap/legorender1.png