I have finished work for Watwet.com - Jordan based startup creating social network around mini-blogging and messages. My task was to create Facebook application. I did it and You can view application page on Facebook.
Application allows to post messages to Watwet users from Facebook interface, new messages on Watwet can set Your Facebook status. Also if You set new Facebook status, then it will propagate to Watwet as new message.
Here You can see how it looks:
Do You need some Facebook application? Go ahead and ask.