Fuck me I'm bored, but I stumbled across this a little bit ago.
Tells you where your surname is most common and loads of other general information, plus the percentage of people with higher/lower status surnames, which US/Aus/NZ state your surname is most common in etc.
Can be pretty interesting...there's two maps, one for 1881 and one for 1998. Interesting to see that the top area for my surname in 1881 was Blackburn and now it's Lerwick, in the Shetland Islands. Seriously, what the fuck is there?