One of the traditions of Christmas is the Festival of Nine Lessons and Carols from the Chapel of King's College Cambridge, this is broadcast live on Radio 4 at 3pm. Earlier in the month another carol service, Carols from King's, is recorded for television earlier in December and broadcast by BBC2 on Christmas Eve.
Normally overseas readers wouldn't be able to share in this BUT the BBC World Service will be broadcasting the Nine Lessons and Carols at 3pm GMT on December 24th. You should be able to listen to it on the internet (use previous link and click the listen live button) but you can check your cable provider here.
The carols and readings vary from year to year with the exception I'll guarantee this will be the first carol.