Brett,

Just stumbled across this post -- wish I'd seen it when I was looking for a replacement for http://expandurl.appspot.com a few months ago! Super quick modification for the AppleScript version: adding...

set AppleScript's text item delimiters to {"//"}
if (count of text items of message) is 1 then set message to "http://" & message

...will add http:// if it's missing. Handy if you're typing the address into LaunchBar instead of pasting it in.

Cheers,
Dan