Excellent. I've been looking for a solution to this very problem. Using Ping.fm in conjunction with Posterous is a great way to make everything work harmoniously. Now I can have status updates go to Twitter, Facebook, and Friendfeed without there being any duplicate posts.
I had a big problem with Friendfeed pulling in too much stuff and getting 4 copies of every update. I would post to Posterous, which would post to Twitter, Facebook, Tumblr, and Friendfeed. Then Friendfeed would pull in Twitter, Tumblr, and Facebook. It was quite a mess.
I'm sure it'll take a little tweaking, but I think this is going to solve a lot (if not all) of my problems I was encountering.
