Are there Video Conference packages that work through a firewall?

Factual Questions
1

Since the WTC tradgey our company is puttin a restriction on travel, so I want to look into ways I can use video conferencing. Are there any good packages that work through the firewall?

We have a dedicated system that works with ISDN, but we want to get something going that can be used from the desktop.

blade

2

Firewalls are configurable to allow/deny access based on protocol, ports, ip addresses and what not. Any decent video conferecing package should work fine. I haven’t set this up personally but doing a quick search on google shows that at least CUseeMe Pro advertises that they have firewall support.