Deadhorse (or should I say Captain Ahab?), use this:

for links within mudcat:
<a href="/urlonmudcat">clickable text</a>
and replace the red parts.

for links to the outside world (if it really exists):
<a href="http://www.outsideworld.com">clickable text</a>
The bold part is important for outside links!

MudGuard/Andreas