nate:maverick: you should only be allowing our IP adress to be talking to your box, if not then yes you are more likely to be open to attack and rememeber you are responsible for full security on your box.
Having port 5060 open is asking for trouble, you definitely need to lock it down asap.
Any hints of doing this without disturbing the current functionality? I admit I haven't had time to see the Asterisk security video, but if there is a quick and dirty way to do it I would much appreciate some help!
Cheers