You can use Google SketchUp to create, modify and share 3D models.

Homepage: Code: http://sketchup.google.com/intl/en/

Download: Code: http://www.megaupload.com/?d=BKON882P
http://www.megaupload.com/?d=YFDSHC1Z
or
http://hotfile.com/dl/11754659/e88a4b4/GSUP7Portable.part1.rar.html
http://hotfile.com/dl/11754713/a38f3a8/GSUP7Portable.part2.rar.html
or
http://rapidshare.com/files/276724448/GSUP7Portable.part1.rar
http://rapidshare.com/files/276724037/GSUP7Portable.part2.rar