I would like to see a forum plugin [phpbb, etc] that would allow forums to move posts to Stackoverflow. It gets rather annoying seeing repetitive questions in forums that are posted on SO or in the forum in another place.
The Stack Overflow API currently has no writing function. The bot discrimination system in use prevents the use of most bots. If you want to migrate posts, your best bet is to do it by hand.
Eventually the API will include posting functions, and the thing you'll need to be careful about then is that the questions posted are good, otherwise the user account (and eventually IP and other methods of tracking it) will be blocked due to consistently poor posts.
But as long as the questions add value to stack overflow, it won't be a problem.
There is no timetable for the post access on the API.
IMO this is a bad idea since it has the potential to reduce question quality and just have all sorts of crap posts pushed to SO for the sake of it (if someone just needs to click a button to add a post to SO from an original forum post they probably will just in case they get a response.)
If all questions on forums were carefully worded, good, on topic questions then I'd be for it. But I suspect all this would bring to SO is more bad questions. If someone really wants to get input from stack overflow as well as a forum and really feels the question is suitable for both, they'll post it in both places.