To start a new renderjob on RenderWorld, you have to enter your email address, and upload your blender (*.blend) file:
Your email address:
Your blender file:

Do you allow renderworld to publicize the content?
Model public?
Textures public?
Rendered images public? (Screensaver, Gallery)
Rendered animation public? (Gallery)

Do you want to make your works available under a Creative Commons License?

If you want to submit your Renderjobs from within Blender, you can download our Submission Tool, install it in ~/.blender/scipts/ and find it in Blender under "Export->RenderWorldSubmitTool".