I finally finished (more or less) my ISO 8601 parser for Obj-C. I'll be using it in my TTL patches for Vienna and Feed, and Colin will use it in the Adium XML logging code.
Right now I'm working on an unparser, for creating a string from an NSCalendarDate. Colin will be using that too. I think he'll be posting more about it on the Adium blog when it's in.