I agree with Alcon, the Republicans will probably lose a few more seats in 2008, but somehow I see them taking one of the chambers back in 2010.
Not likely. If they lose even more seats in 2008, they need a wave in 2010 to retake the House. 2010 might be a fairly good GOP year if we elect a Dem President, but it's doubtful it'll be a 1994/2006. The new Dem House will probably last at least as long as the old GOP House did.
As for the Senate, the GOP are looking pretty bad in 2008, their best case scenario is probably breaking even. In 2010, the map doesn't benefit them. In 2012, well yeah they'll pick up just thanks to the last two elections in that cycle being so great for us, but can they pick up enough to retake the Senate? Depends on how the next two elections go, but it's possible but not all that likely.