[CentOS] Ham Radio s/w and CentOS? {including Echolink}

I am going to present Linux to my ham radio club at some point in the next few 
months, and wanted to collect info on ham radio software, including options for 
echolink.   Our repeater has an echolink connection, thus if I present the 
software available for it, it might perk up people's interests more.

It would also be very helpful if the echlink applications offered 
proxy/firewall options so people at companies or at home that have networks 
that implement firewalls, can proxy out and still get on Echolink.

Also, anyone know of a live-on-CD/DVD CentOS distribution that may include 
Echolink and/or other ham software?

Thanks for any leads.

Scott, WY1Z