Saw this today on one of the computer boards that I frequent.
http://www.blender3d.org/
Supported Platforms
Mac OS X
Windows 95, 98, 2000, XP, ME, NT (i386)
Linux i386
Linux PPC
FreeBSD 4.2 (i386)
SGI Irix 6.5
Sun Solaris 2.8 (sparc)
I downloaded it and played with it for a few minutes, looks really nice. I'm going to try to learn how to use it just as soon as I have some spare time.