>>13
According to a couple of dictionaries I look at, they are pronounced the same. The spelling is different because they come from historically different words.

And English is not very descriptive about how it should be pronounced, take for example the -ough example:

tough (UFF)
cough (OFF)
bough (OW)
through (OO)
thorough (OH)
and even:
hiccough (UP)

Thats six ways of pronouncing -ough. English spelling is certainly not helpful for indicating pronunciation.