Instore at Sainsburys (in Didcot store today), selling buy-one-get-one-free internet VOIP phones (USB corded connection), total £12.99 for the pair. Think these are on clearance now, not sure how widely available they are in other stores.
Comes with a "100 minutes" voucher and software to connect you to http://www.freshtelinternetphone.co.uk
- lets you allocate yourself a new, normal-looking local phone number in your area to receive incoming calls. Free internet calls to other freshtel users, and probably more useful calls to Tesco branded internet phones are free too.
As the phone is a USB audio device ("Celestia C1085"), it works fine with Skype/Voipcheap etc. as well - I have also checked it on Vista too and no problems there.