It took a bit of time but I removed it... HTML will work the same in here as it will on any page. Basically,
<A HREF="http://www.microsoft.com">http://www.microsoft.com </A>. If you forget the http:// part your browser treats it as a page somewhere on this site. If you forget the quotes, it won't work. If you leave off the closing </A> the whole page will become a link.
However, I'm working on forum code that can auto-link all http:// addresses... it seems to be working OK, but I want to test it for a while first.