To be fair, Pandora just announced they're stopping their UK service. That means blocking access to UK IPs.

You should still be able to access Last.FM in a heartbeat though. I've never been able to access Pandora from Canada and wasn't down with subscription internet radio anyway. I use Last.FM along with a number of other resources to find new artists and music, but to tell you the truth I rarely ever listen to a radio-like stream from them or anyone else.