I've heard both.
in reply to a message by Chrisell
I think it may be a regional thing. In DC, I'll hear jac-o-bee (Don't ask me to do the accents, I can never do that) more often that not. In the midwest, I hear jah-ko-bee.
Edited to elaborate
Edited to elaborate
This message was edited 8/6/2006, 8:26 AM