If elections were held today and results corresponded to polls, the Senate would be 50-49-1 Republican.
That factors in Lamont (D) winning in CT and Republican incumbants DeWine (OH), Burns (MT), Santorum (PA), Talent (MO), and Chafee (RI) getting knocked off. Also, narrow leads in NJ, MD, and MN have to hold.
For the Democrats to become the Senate Majority in 2007, they need to win in either Tennessee (where Harold Ford trails three Republicans slinging it out in the primary) or Nevada, where a safe GOP seat has moved into single digits.
Polling data can be found here, here, and here.