The first poll of NH to be conducted after the results from Iowa were in shows a decent "bounce" for Barack Obama, but not for Mike Huckabee.
On the Republican side, Rasmussen has McCain moving ahead of Romney 31%-26% in NH, with Huckabee running fourth at 11%, trailing Ron Paul's 14%. This represents a precise reversal of McCain and Romney's standing, while Huckabee hasn't moved at all.
Post-Iowa "bounces" in the past have often increased a few days after the Caucuses, so this is hardly the final word. But right now the CW that Obama and McCain became front-runners after Iowa looks reasonably sound.
UPDATE: Two other post-Iowa polls of NH came out today showing a less pronounced Obama bounce. The CNN/WMUR poll has Obama and Clinton tied at 33%, with Edwards at 20%. Their previous poll, taken between Xmas and New Year's, had Clinton up 34-30-17. And the Concord Monitor poll has Obama up 34-33, with Edwards at 23 (their previous poll was too long ago to provide much in the way of trend analysis).
Both these polls closely track the Rasmussen findings on the Republican side, with John McCain holding a six-point lead over Romney, and Huckabee mired in the low teens.