I would recommend going the SIP route by setting up an Asterisk box somewhere and buying a DID and upstream capacity and then using it with whatever clients you

I would recommend going the SIP route by setting up an Asterisk box somewhere and buying a DID and upstream capacity and then using it with whatever clients you want. Asterisk can be run on a whole load of hardware and I know of a few people who run it on their home routers (beefy enough as these routers are, they're far from industrial standard) and so far I have yet to hear any complaints from them. I've been using the Android native SIP client with an asterisk box and it works really well. Be aware though that it doesn't allow you to make calls over cell data, but rather limits you to making/receiving calls on Wifi only. In terms of upstream providers the only one I know of in Europe is Blueface[2] as a few of my friends at home in Ireland use them in their homes [2] - http://www.blueface.ie/residential.aspx http://www.blueface.ie/residential.aspx