Here is a hard drive enclosure I found on ebay. This is the same guy that I bought mine from. They're nice and small and cheap, too!
http://cgi.ebay.com/2-5-INCH-USB-2-0...QQcmdZViewItem
As for the hard drive, just do a search on ebay and look for a 2.5inch laptop hard drive. I just lkook for the biggest capacitry, cheapest drives I can find.