Research 2000 (6/2-4, likely voters, 5/24-26 in parens):
Blanche Lincoln (D-inc): 45 (44)
Bill Halter (D): 49 (47)
Undecided: 6 (9)
(MoE: ±4%)
One caveat here is that this sample claims that they voted for Halter over Lincoln by a 48-46 margin (with 3% for D.C. Morrison and another 3% who didn't vote) in the first round of voting. Lincoln, as you recall, narrowly claimed a first place showing three weeks ago. However, it wouldn't surprise me at all to see enthusiasm among Lincoln voters dimming (especially after witnessing her sadsack runoff campaign), so these numbers may not be out to lunch at all.
DailyKos decided to take a pass on polling the general election match-ups this time, but that will be the next hot topic after Tuesday.