Using the yahoo polling tool here is my prediction:
If McCain Wins PA:
McCain 281
Obama 257
If Obama Wins PA:
McCain 260
Obama 278
PA is do or die. If Obama wins FL, or OH it's over for McCain. It's looking like Obama is going to win PA, but hopefully that won't happen. Without PA, McCains only other real chance is to win CO, which gives him a chance for a tie and then ME and NE will decide based on congressional district.