We have set up a VOIP account with Sipgate, they have allocated us a local UK number which we can use in Aus - people will call the UK number and we can talk online, we have tried it out and the number works and we can dial out, we still need to get a proper VOIP headset though. I think it's 1.9p a minute to call UK.
Anyway, has anyone any experience of them? And is anyone uses VOIP, what sort of headset, or phone should I get to use with it??