Just saw your message Callfan - I used a German T-Mobile voucher to top up my mother's T-Mobile UK prepay account late last year. I got a sensible rate of exchange too.
Vodafone also allows this facility, albeit only in Europe.
Orange doesn't support this facility.
I thinkyou can also top up a T-Mobile prepay account online via the
www.t-mobile.co.uk Web site.
Hope this info helps... Steve
[size=2]Steve Gold
PO Box 1014, Sheffield S10 5YG, UK
Home mobie: Telefonica O2
Other UK mobiles: 3, Vodafone, Virgin
Foreign SIMs: Toggle (multi); Germany (Fonic); Poland (Orange PL);
Skype: stevewgold