A quick link roundup:
“The following provides some guidelines for the user interface define of becoming an OAuth service provider”
Detailed notes on UI issues, with screenshots and links to related work (opensocial etc.).
Myspace’s OAuth Testing tool:
The MySpace OAuth tool creates examples to show external developers the correct format for constructing HTTP requests signed according to OAuth specifications
… to help developers cure their OAuth woes. You can use the Playground to help debug problems, check your own implementation, or experiment with the Google Data APIs.
If anyone figures out how to post files to Blogger via their AtomPub/OAuth API, please post a writeup! We should be able to use it to post RDFa/FOAF etc hopefully…
Finally, what looks like an excellent set of introductory posts on OAuth: a Beginner’s Guide to OAuth from Eran Hammer-Lahav.