While waiting for Asterisk 1.4 to make it's way downstream to Ubuntu, I've decided to give AsteriskNow (inside a Virtual Machine) a go. I figure that way I can get most of the setup right before I upgrade my real machine.
The new Asterisk comes with a web based UI. So far, it's seems a little flakey - I can't add users (I keep getting a "Sorry, user must be undefined digits". Still, it's new, so it's bound to not be quite right.