Is it possible to have a forum update facebook or twitter?

Like for a news section. Once posted it will automatically update facebook or twitter.

Is it possible through the API?

At the moment it is possible through the API (provided Facebook & Twitter APIs support automated posting/updating - I've not looked at either for while). However would be quite complicated to setup with having to regularly check for new posts/updates.
Having said that, we do have a new API feature planned which will make it easier but would still require good knowledge of how Twitter/Facebook APIs are working.

Ahh ok, then I should read about their API's. I'm not worried to much about Twitter though, when I update facebook, it updates Twitter.