For those of you that don't know Renderosity.com is a web site community for 2D and 3D artists! There are lots of great free downloads of all sorts including object models, backgrounds and other free downloads for other 2D and 3D-related programs like Bryce! There are also message forums and contests and artists have their own marketplace stores where you can purchase their 3D stuff.
If you join the site (it's free to join) and become an affiliate member then you will be able to earn money when you "refer" new members to them.
There are some rules though. First the new member that you refer has to purchase something from the site within 60 days of their joining. When they purchase something within that time period then you get a percentage of the sale. You can either get paid by regular check or by Paypal. You also have to chose a minimum payout amount ($35 or higher).
I still see that a lot of members from the Renderosity.com site still have a few questions about the program - most of those questions answered on the affiliate program page.
So if you're interested in making some extra money online then you should definitely check it out!