At the Corner, Mark Krikorian has a list of people he thinks are fairly strong against cloture:

The solid No votes on cloture are Alexander (R-Tenn.), Allard (R-Colo.), Baucus (D-Mont.), Byrd (D-W.Va.), Bunning (R-Ky.), Chambliss (R-Ga.), Coburn (R-Okla.), Corker (R-Tenn.), Cornyn (R-Texas), Crapo (R-Idaho), DeMint (R-S.C.), Dole (R-N.C.), Dorgan (D-N.D.), Enzi (R-Wyo.), Grassley (R-Iowa), Hutchison (R-Texas), Inhofe (R-Okla.), Isakson (R-Ga.), Landrieu (D-La.), McCaskill (D-Mo.), Pryor (D-Ark.), Roberts (R-Kan.), Rockefeller (D-W.Va.), Sanders (I-Vt.), Sessions (R-Ala.), Shelby (R-Ala.), Smith (R-Ore.), Stabenow (D-Mich.), Sununu (R-N.H.), Tester (D-Mont.), Thune (R-S.D.), Vitter (R-La.).

Senators seeming against the bill but leaning toward cloture (emphasis added):

The following 12 senators are leaning against the bill itself but so far are leaning toward the cloture motion — which means, in reality, that they would be helping pass the amnesty, because if the bill comes to a final vote, it will pass. These are the Senators whose decisions will likely determine whether the amnesty passes or not: Bond (R-Mo.), Bingaman (D-N.M.), Burr (R-N.C.), Boxer (D-Calif.), Cochran (R-Miss.), Conrad (D-N.D.), Ensign (R-Nev.), Levin (D-Mich.), Gregg (R-N.H.), Nelson (D-Neb.), Hatch (R-Utah), Webb (D-Va.).

Okay, a few points arising from this list:
On Switching from for cloture to against:
Is Stabenow really going to switch to vote against cloture? Has anyone else heard about this?
Is Levin on the fence? He was for cloture last time....
Conrad could certainly be in play; he fellow ND senator Dorgan is a prominent bill skeptic...
Could Sherrod Brown (D-OH) be a plausible addition? Is he still undecided?

And these Republicans:

Collins (R-ME)
Snowe (R-ME)
Domenici (R-NM)
Murkowski (R-AK)
Stevens (R-AK)
Warner (R-VA)
Bennett (R-UT)

Are they all now firmly pro-cloture? Are they OK with the "clay pigeon"?

And where's Coleman (R-MN)? He's sounded pretty critical of the bill, but has he switched?