Skype. An alternative, free, telephone service.

[Jakemaster]

We used to use it on US Tour.

[beaky]

I DLd it, but had a hardware problem: microphone is always routed to speakers. Haven't bothered fixing that yet, but I will.
It should be noted here also that skype now comes with video; that's pretty cool.

[Brett_Henderson]

I Use Teamspeak - as far as I can see there is no real difference to Skype - you both have to download free software, you both have to be online & they are both free.

Teamspeak and Skype are quite bit different. Skype is crystal clear and full-duplex (like a phone .. you can just talk, even at the same time.. no push-to-talk .. or .. voice activated talk).. They both have the limitation of needing to be AT your computer. Cell phones are so cheap, and are with you all the time. I don't even have a regular phone any longer. My "phone" line runs straight into the DSL modem and that's it.