The phone itself will be fine, the American's tend to use the same 10 digits as ourselves when dialling numbers. The problem will lie in the phone jack (plug) which will look more like the one used for a modem than a phone, this can be easily solved by visiting your local electronics store and purchasing a converter for around �1.99.
UK telephone plugs are BT431 and the US will be RJ-11/14 style (for reference)