However low the President's approval ratings have dropped, Republicans would like to have you believe that the problem is isolated to him, and that the members of Congress who enabled him on everything from Iraq to the budget, are inured against the consequences of their actions. Alternatively, when defending the President, they like to cite polls showing that Congress is unpopular (a generic poll, so pretty much useless in relation to individual members) as proof that Democrats fare no better than Republicans.
They may want you to, but don't believe it. At the very least, the problems for the GOP are beginning to filter down into the Senate. job approval ratings on all 100 members of the U.S. Senate show that of the twenty-five Senators with net approval ratings in their home states above 30%, only ten of them are Republicans (note that the party ID is in column 4; the color of the state name in column 2 tells you who won the 2004 Presidential election in that state.) Conversely, three of the five Senators with negative net approval ratings are Republicans, and all three of them are up for re-election this year; additionally, fourteen of the 22 U.S. Senators with net approval ratings of ten or less are Republicans.
Not overwhelming numbers, I will admit. There could also be a lot of reasons for this in individual states, but as a national snapshot, this makes it pretty clear that on balance, voters in the states prefer their Democratic Senators more than they prefer their Republican ones.