I don't know of any that are truly real time. Plus, I don't think true real time is a realistic expectation. That would mean that a bunch of IT pros are just sitting around all the time waiting for questions to be asked or, worse, hanging out in a chat room.
The value of message boards (IMHO) is that you don't have to be present to get the benefit of a distributed group of people (who are in different time zones). And with notifications via e-mail and RSS, you can get updated as soon as responses come in. I think that is as close to real time as you're going to get (while still getting quality information).
In the Workspace featureset, we have implemented a feature called Updates. It will show you up-to-date information on the discussions that you've participated in. The Updates view is helpful for someone when they are on the site and want to keep up with changes in near real-time.
To see Updates, click the My Workspace link at the top right of the page.