Well you can use mobile's to top up your PayPal account and so they should have something where you can top up your phone
I was looking at the carphone warehouse mag and came across something called MONILINK. It lets you top up your phone (or someone elses) directly from your bank and at the moment they'll give you £10 free just for doing one transaction. I did a balance enquiry for 20p and got £10 free. Bargain! Check out the CPW site http://stagml.monilink.co.uk/cpw Hope this helps!
Signed up as I am with HSBC - further research on Google suggests monilink will be adding more banks to the service, along with other services Registered and downloaded the application to my mobile phone, just waiting for my activation code to drop through the post!!
Well, I think it all depends on the Service Provider that you are using ? If they support it then why not, if not then you have a problem.
it mentions on the monilink website that Vodafone, 3, Orange, T-Mobile, O2, Virgin and Tesco all support the service - that's all of them, not sure which other operators there are