Apparently they're trying to get him for at least one of them. No news on if they have or not. But apparently he's in an episode airing on sky in a couple of weeks
I'm personally looking forward to these. I would have prefered they can Atlantis (which I love, don't get me wrong) and carried on SG1. SG1 has been more consistently good, although its had its bad episodes...what series hasn't.
I also don't see why everyone is so fixated on O'Neill, saying the show needs him...it doesnt. Season 9 was pretty good and Season 10 has brought some of the best episodes ever made for Stargate...its continually improving