For all the Brits on the forum, I have just been over to the UK and purchased a Tesco Internet Phone, which give me a UK phone in the house for receiving and making phone calls with. What I purchased was a Tesco IPA 1000 internet phone Adapter.
http://direct.tesco.com/q/R.100-9564.aspx This is a separate UK landline phone to your Swiss one.
If you have an internet Router and a traditional UK telephone with a BT socket (American phone may work) you can have a UK number in CH through any UK telephone Exchange that you wish, ie you choose the UK exchange that you want to be linked too.
I chose Manchester, since we have a lot of family there, so I have a 0161 number and if this number is dialed in the UK, then the phone rings here in CH.
To make out going calls to the UK its GBP 0.02/ minute and you just dial the number as if you were in the UK ie 01234 567890. Tesco do give you a GBP 5.00 start up voucher.
If friends and family have a Tesco Internet Phone calls are free.
What is good about it, is that there is no pc involved, other than the internet registration.
http://www.tescointernetphone.com/
It may be not as cheap as skype, but I don't have to worry about the PC.
Call quality is good, there is voicemail included. To access voicemail dial *123
Tesco Direct will ship to CH,
Downside - The power supply has a UK plug on it and you need a separate phone. But I am impressed.