Voxalot / SIP Broker Support Forums - Voxalot on Mobile phone

Apologies in advance, am a newbie to all of this.

I have been trying to find out about using voxalot on my mobile (cell) phone. I have seen the thread titled "Nokia eSeries Support", and am intrigued.

Could someone point me in the direction of an explanation as to how this works, and what capabilitieas my phone needs?

1) Am not talking about the web callback, have got this working fine.
2) What devices support config to voxalot?
3) Would the phone need to be unlocked from the network?
4) I'm assuming I will be charged by the phone network to be connected to the internet whilst on the call, is this via WAP / GPRS?

There don't seem to be many articles explaining this, probably as the mobile phone companies don't want us to do this as it bypasses their charges?!