From Public Policy Polling (whose work was outstanding in 2010):
if voters in the state could do it over today they'd support defeated Democratic nominee Tom Barrett over Scott Walker by a a 52-45 margin.
The difference between how folks would vote now and how they voted in November can almost all be attributed to shifts within union households. Voters who are not part of union households have barely shifted at all- they report having voted for Walker by 7 points last fall and they still say they would vote for Walker by a 4 point margin. But in households where there is a union member voters now say they'd go for Barrett by a 31 point margin, up quite a bit from the 14 point advantage they report having given him in November.
By way of reference, Walker won 52-46, so this poll represents a 6 point shift since the election.
The most interesting finding of the poll is that much of the shift is among REPUBLICAN union members. Republicans have won more than a few elections by convincing a significant percentage of union workers to focus on social issues rather than on their economic self-interest. In 2010 Walker won 40% of the vote among union families. As PPP notes:
Only 3% of the Republicans we surveyed said they voted for Barrett last fall but now 10% say they would if they could do it over again. That's an instance of Republican union voters who might have voted for the GOP based on social issues or something else last fall trending back toward Democrats because they're putting pocketbook concerns back at the forefront and see their party as at odds with them on those because of what's happened in the last month.
The importance of this shift should not be underestimated. The GOP Governors like Walker are in the process of angering a part of the electorate that they have been holding their own in since the Nixon Landslide of 1972. The fact that this group has shifted is nothing less than an earthquake.