PearlBrian, did you end up getting it to work? I'm about ready to throw my captivate in the trash - I've spent the past 3-4 hours trying to get the damn thing to work with my computer and had no luck.
Installed and uninstalled and re-installed both the "big" pack of drivers originally posted, as well as the smaller updated captivate only package posted on the Samsung website, rebooted many teams, put the phone into debugging mode and took it back out, enabled USB Mass Storage, mounted the drives from the pull down menu and so on in ALL sorts of various combinations and nothing seems to work. When I plug it in, I get a window that says "USB Device Not Recognized" and it goes on to say that the device has malfunctioned and to try reconnecting the device, if the device still does not work after reconnecting replace the device. In the device manager, it's simply showing up as "Unknown Device".
EDIT: Rebooting the phone seems to be working... why didn't I try this HOURS ago.
I'm at the end of my rope here - this is not how getting a new toy should work! Any suggestions? I'm on Vista64 as well.
I'll reboot the handset (can't believe I haven't tried that) and give DoubleTwist a whirl, just in case... otherwise... it might have to go back.