As a developer of iOS frameworks and libraries, I will vouch for cocoacontrols as a solid site. It's easy to add a new entry and search for existing controls by license.
+1 on cocoacontrols! I did not yet contribute but the content provided is great.
I recommend it to many other iOS dev looking to get things done without re-inventing the wheel.
thanks, jeff. glad you like it! :) also, thanks for submitting nimbus just now!