I believe you can change PS to work in the UK - I remember seeing a sticky about this for PS2 a while back. Have a look through threads to see if this still applies. I'm guessing there shouldn't be a problem.
But before you buy PS3, do check this thread too so you don't get caught out with some Hosts:
If you upgrade and don't get a problem with your host, can you add the name of the Host to the list so others don't run into problems?