There is a new service, powered by TopUp2Talk, at
www.80550.co.uk which allows you to send a text from your mobile in exchange for £5 worth of call credit. Also 4p a minute to mobiles at the weekend.
You can use the service from any phone, using the PIN which is texted to you, except a landline that is already registered with TopUp2Talk.
It is best to use the 80550 service from your mobile or your 'friends' phone. For the home phone, the TopUp2Talk £1 top up on 0901 366 4067 works out cheaper - I use it all the time for my international calls.
BTW - I only found this website today. I think it is great. Been reading all the posts and I find the comments about 18866 etc very interesting. When I first found their website I suspected that they were part of Telediscount. I have to admit that I have never tried them because with having BT, CPS with an alternate and a mobile the idea of adding a 4th telecom payment just to save a few extra pennies seemd to be more hastle than its worth.
Now to go and read the rest of the posts.