From First Read:

Barack Obama has overtaken Hillary Clinton in the NBC NEWS superdelegate count with the endorsement of Hawaii’s Dolly Strazar. This is his second of the day and puts him now officially over the top, 277-276.5.

Obama has now picked up 21 superdelegates since last Tuesday’s contests in North Carolina and Indiana. Clinton has picked up 1.5

The NBC NEWS delegate counts:
PLEDGED: Obama 1,590, Clinton 1,426
SUPERS: Obama 277, Clinton 276.5
TOTAL: Obama 1,867, Clinton 1,702.5