I wouldn't know of a decent thread to recommend, but Scott Michaels book Aquarium Sharks and Rays:http://cgi.ebay.com/Aquarium-Sharks...ItemQQimsxZ20090524?IMSfp=TL090524148001r9622 is a decent start. Someone on this site was selling one recently actually... The one thing I must say is that all the "minimum size recommendations" NEED to be doubled.
Big tank, clean water, lots of food, and they're pretty easy. Do a bunch of research prior to ensure you set up a proper aquarium/pond/enclosure. There is actually a site with forums dedicated for this: http://www.sharkraycentral.com/