rockyracoon,
Good eyeballs, brother! Yes, the OP does say he has the bolts out. That's a good tip about marking the two flanges, too. (You're doing a good job dispensing help, lol.)
So, what about some PB Blaster to loosen up the rust/corrosion products between the flanges? Once it has worked for 10 or 15 minutes, you can then tap in a thin metal spackle trowel in between the flanges. Gentle taps to ease the flanges apart and don't let the driveshaft drop onto the garage floor (put a cardboard box or some other cushion under it).
HTH,
Chris