[plug] Whats a good SIP/VoIP soft phone for linux/how to handle nat

[W.Kenworthy]

Whats a good SIP/VoIP soft phone for linux (linphone, gnophone,
SimpleH323, ...)  I need something simple to set things up with the
least hassle, and then perhaps something good to actually use - if they
dont overlap(!)

Is anyone using the h323_conntrack module from the netfilter extensions?
- current snapshot is broken and I'm wondering if its worth fixing? I
need to run H323 through a gateway - will this cover SIP as well?  Is
there a "better" way to do VoIP through a nat'ing iptables firewall?
(iax, asterix, ?)

BillK