Thanks Aesir - I'll give that a try.
Quality? no experience of the "tunnel" audio, but I've had to ask my Dad (partially deaf/tinnitis from flying RCAF North Stars - DC4s with Merlins, props exactly in line with the cockpit...) to use headphones as otherwise I hear my voice booming back at me.
Also agree that it's a better form of text messaging than MSN - no limit to the amount of stuff in each message, and you can separate longer spiels into paragraphs.