Odeo
Last one to mention it, I’m sure, but late last Friday (hopefully the last late Friday night spent at the office) Odeo opened the doors to the directory/sync portions of the site. The Flash based studio is still in beta-invite, but look for it soon.
On a semi-related note, don’t mix ActiveRecord and Ruby threads and hope for reproducible, reliable, thread safe results. More on that when I get back from Peru.