Ok, here is the deal of the week, a Nokia 5800, touchscreen, wi-fi, GPS, it will allow you to use your voipcheap.co.uk account through the phone using either wi-fi or the GSM wireless network and the beauty about is that being on T-Mobile, if you have a Virgin Sim Card, it will work in the T-Mobile phone and that means you can access the data network for £0.30 pence a day up to 25 megs, which is plenty for making voip calls.
Here is a link to the other phones that run the app from voipceap uk (this is not voipcheap.com, they are separate) - not all the phones on this list are wi-fi which is a must if you want to make free calls during your free days period which you get when you top up your voipcheap account:
http://www.lowcaller.com/en/get-lowcaller-now.php?label=Voipcheap.co.uk
Once you have found your model of phone, you will need to install the file on your phone probably via your pc as I did with the Nokia PC Suite. Once it is installed, I found the app in the installations folder called M.V - it is a simple but nice app you simply enter your voipcheap uk username and password, choose the method of connection either wifi or GSM network, the app will register you to the voipcheap server and that's it! Choose a contact from your phone book and enjoy free or cheap calls. You have to insert the international dialling code for the country you wish to call even if you are in the UK calling a UK landline number e.g. you would dial 011 44 miss out the first zero and the rest of the number will follow like this:
011 44 123 456 7890
Enjoy!