Pretty much every locavore-leaning resto in town has them on the menu at this point I'd imagine. (I just enjoyed a nice olive oil-poached halibut with ramps and fava beans at Boulud Sud.) Rucola had a foraging trip recently and was giving them away -- I imagine they're serving them as well.
They were also at the Union Square greenmarket two weekends ago -- the best value was the egg sellers on the west side of the park, who were selling very nice sized bunches (perhaps two dozen ramps a piece) for $3. (Someone on the north side of the park was selling bunches of maybe 8 ramps for $6 -- that was probably like $40 a lb.!)
And missmasala is correct that they were at Carroll Gardens this past week, along with a small amount of fiddleheads.