http://www.hangsim.com/vsf/ - Vehicle simulator main site.
http://www.hangsim.com/mf/ - Micro flight main site.
http://www.hangsim.com/vs/ - Virtual sailor main site.
http://www.avsim.com/ - AVSIM library.
http://www.wings3d.com/ - Wings3D a free 3D modeling program.