I can offer a bit of advice and possibly even a solution.
Advice is simple, get a headset. Heck, steal your sister's Ipod ear phones if you must. Anything that goes from the PC to your Ear and produces a sound kind of resembling music or (better yet) human voice will do. A Microphone attached to said device is nice but not crucial.
Next step is find someone with a Ventrilo server. (google or
www.ventrilo.com)
As Ventrilo server's can't be run off an end-user's PC* (Thats you.) you're much less likely to find your team mates sound like 4 inch tall swamp monsters with a bad cold. If you use that other Voice communication (aka Voice over Internet Protocol or VoIP) program then... er. I'm sorry. ;p
Voice Comm, for all it's current short comings and flaws, is simply better. One thing to remember, Ventrilo doesn't REPLACE in game chat, it SUPPLEMENTS and COMPLIMENTS in game chat. Control + L Click/Space Bar is far Superior to saying "I have cripple on me" and expecting your teammates to actually know who you are and to find your slightly pink health bar. Calling targets without Ventrilo though... forget it. Couldn't pay me to do it. Sure, initial target is ease, but unless you just found the greatest spike build since (heh) or you're facing a team that thinks all monks are good for is healing, you'll most likely be target switching to, erm, forgot I'm not writing a guide to PvP.
The solution I may be able to offer is my Ventrilo server. Yes, I pay some bucks a month for its hosting, but it's free to use. I'm going to say this only once and it's your only warning; it is heavily moderated and anyone being annoying, stupid, offensive, or disturbing will be banned. Thats it, no questions or warnings. As a guide to what will get you banned, just use your head, racism? Yup. Sexual harassment? You bet. Acting 15? Sure thing. Being 15? Ice Cube's chance in a microwave, but you got a chance. ^^ If you didn't understand the last paragraph, please, don't waste your time connecting or my time banning, thanks.
Login information is found on my guild's website,
www.rubiconbreach.com
It's nice if you ask me (Zero in Ventrilo) or any other "main" admins permission to use the server, but if you're just using an empty team room and not bothering anyone then you have nothing to worry about. =] Main Admins have a private office at the bottom of channels BTW.
P.S. There may or may not be another voice communication program some people use.[OPINION] It sucks. I don't wanna hear about it. Thats pretty fair I think, because we can barely hear anything on it![OPINION] If someone wants to write about it, please do. Choice is good. As long as that choice is Ventrilo, Vodka, and Venti.