Slate's Delegate Calculator at http://www.slate.com/... has been updated to reflect the additional 6 delegate votes Obama has acquired in Texas and Mississippi.
Currently Slate's indicates H. Clinton would have to get 65% in each of the remaining Primaries to pass Barack Obama's pledged (elected) delegate vote total. She would still need another 404 superdelegates votes to win -- about 150 more than she currently has.
Assuming the remaining primaries split 50-50 Obama would lead by 164 delegates and would need another 324 superdelegates -- that is, 104 more than he has now.
UPDATE 4/22
Slate's Delegate Calculator has been updated for the PA results as well as the net +2 gain for Obama in the final Ohio certification. It now indicates HRC would need 69% of the vote in each and every remaining primary to get the lead in delegate votes.