My FriendFeed cocoa classes are now fully functional except including media enclosures in posts. I ended up rewriting it to use NSXMLDocument rather than PSFeed, which doesn’t involve any more code and eliminates the dependence on PubSub.
Now that that’s done, I’m digging into the Pownce API. Pownce isn’t much more complemented, but it requires an API key, which was one of the reasons I had avoided it. Fortunately the API key is no big deal. You just fill out a request form and get the key immediately; it doesn’t have to be approved if you’re just creating a key for testing.
Once I finish the Pownce code and make a less ugly demo program, I’ll release the source code.