You can set yourself up to be a server. Make sure you have some bandwidth; it kind of helps. You can download the server program from www.goteamspeak.com. You will have to set your router up to forward port 8767.
I think there are also some free servers out there that might allow you to use TS.
Don't use teamspeak or ventrillo use skype. It has great sound quality better than phone line calls and it free. It's awesome my guild mates and I use it all the time.
a lot of guilds will use either teamspeak (TS) or ventrillo (vent) to talk during the game but you must connet to a server. my guild has a TS server that we use just to talk to each other and you must run the program seperatley from guild wars. However you can only talk to people on that server. IE there is a part of 4 two from my guild 2 from another i can only tlak to the guy in my guild not the other two. there is not in game micsupport as i know of