hmmm.
might be my isp. But none of my UK friends could connect. Probably a propagation lag or something. but it should work without propagating.
As you are running your own php and apache(whatever OS you are using)
probably you would need to tweak http.conf to allow mod rewrite and write a .htaccess for it to go to a folder when using a subdomain
just a suggestion but it doesnt work on IE and FF both on mine and friends with diff ISP
edit:
Rumour about gaim is true
http://gaim.sourceforge.net/
"Working at Google
I (Sean) have been hired by Google, moved to Seattle, and have been working on the Google Talk team for about a month and a half. The goal of Google Talk is to make real-time communication as open as possible, and in that regard, I've been working to offer all of Google Talk's features into other clients. Currently, I'm working on making it as easy as possible for other clients to use Google Talk's voice features. You can expect Gaim and other clients to be interoperable with Google Talk's voice features in the near future. "