Are you an iOS 5 developer? Have you paid up on your membership and accepted the NDA agreement? If so, bit.ly is opening up a new iOS 5-specific SDK.
The new SDK allows iOS apps to integrate branded bit.ly shortcuts into the previously-announced new Twitter services. Branded shortcuts include TUAW's in-house aol.it links, for example.
Due to iOS 5's pre-release status, you must apply directly to bit.ly (drop them a line at email@example.com) and clarify your NDA-status in that e-mail.