Places to go for free stuff
http://www.turbosquid.com/ use the search funtion for free 3d they have lots.
another, you can spend days here
http://www.3dlinks.com/
yet another
http://www.the3darchive.com/index.html
And an easy free 3d program to make your own
http://wings3d.com/
And a file converter for different formats
http://www.quick3d.com/ it has a 30 day trial
And if you are into modeling humans this program is really cool
http://www.dedalo-3d.com/index.php