>The ultimate setup would be a Wifi Phone, but I cant find any on the net.
The Zyxel 2000W is readily available, but the price is ~£145 (was ~£185 few
months ago).
Apparently it works well, but does not like Wifi encryption.
There are others, see:
http://www.square7.com/
but their prices aren't so good either.
You may want to consider Zyxel 2602HWL WiFi router with two VoIP ports,
different registrar and landline pass.
Mine works fine with Sipgate (free in) , Voipbuster (free out).
(broadbandbuyer.co.uk was selling them at a wrong price

Regards,
Martin