I posted this in the Captivate forums but it worked on my wife's Vibrant too, so I wanted to share:
http://androidforums.com/samsung-captivate/134390-new-fix-gps-using-wifi-instant-lock-indoors.html
http://androidforums.com/samsung-captivate/134390-new-fix-gps-using-wifi-instant-lock-indoors.html