Siena College (PDF) (3/25-26, likely voters, 3/9-10 in parentheses):
Scott Murphy (D): 47 (41)
Jim Tedisco (R): 43 (45)
Eric Sundwall (L): 2 (1)
(MoE: 3.2%)
If I had a Drudge siren, I'd be breaking it out right now. There's been blogosphere whispers for the last few days of various leaked polls showing Murphy within a point or two or even up by a point, but nothing quite of this magnitude: Scott Murphy has turned a four-point deficit from two weeks ago into a four-point lead in a public poll. Before we start dancing in the end zone, though, we have to remember that this is a low-turnout special election, and whatever happens is going to be decided by GOTV and ground game. Even if we're peaking at the right time, the key is going to be actually getting those Murphy voters to the polls.
The GOP registration edge in the district isn't helping Tedisco much. Part of the problem is that Murphy has the support of 84% of the Democrats, while Tedisco has the support of only 64% of the Republicans. The poll also has crosstabs of the regions within the district: while Murphy is remaining steady in the region he's from (Essex/Warren/Washington Counties), he's gained 8% since last poll in Rensselaer/Saratoga Counties (to 43%) and 7% in the Hudson Valley (to 46%). Combined with his 58% in the north, that's enough to put him over the top.
There's still one wrinkle in this poll: it includes Libertarian candidate Eric Sundwall, who got kicked off the ballot yesterday for not having enough valid petition signatures. While I'd expect more of Sundwall's votes to migrate to Tedisco than Murphy, some of his would-be voters may simply stay home, and at any rate, Sundwall's share in this poll is still smaller than the Murphy/Tedisco margin.
UPDATEby James L.: A new DCCC poll has Murphy leading Tedisco by a 43-41 margin. No details are available yet on its sample size or the name of the outfit that conducted the poll.