This from Rasmussen:
Democrats lead 46-38 on Congressional ballot.
"Except for a few days when the issue of gay marriage was in the news, republicans have held steady at 38-39 percent while during the same period with the same exception, Democrats have been in the 43-45 percent range for most of the month. For most of 2004 Democratic advantage (on congressional ballot) has been 4-7 points.
http://www.rasmussenreports.com/Congressional_Ballot_Survey.htmThe Democratic advantage on congressional ballot has been about the same or better than the GOP advantage was in 1994 when they won back the House and Senate. I think Democrats have a shot at doing the same thing.