I use Simple Facebbok Conect Plugin in my site.
Plugin works perefctly, but NOT SUPPORT CUSTOM POST TYPES.
For example in my site have SLIDER (CUSTOM POST) but I don't want that when I add one it be published.
So I modify plugin code and send it via mail to Samuel (Otto) 2 weaks ago, but have not received any response from him.
If someone is interested to this update, that publishing on facebbok only the types selected in configuration, reply to this post: I will send the file modify via e-mail.
P.S. @Otto: As I wrote in the email, I'd be happy if I could help you in updating of Simple Twitter Connect plugin. So if you want send me a copy of the latest version... ;-)