londrum - 7:58 pm on May 8, 2009 (gmt 0)

it might be one of those proxy hijacking things
try doing a search in google for inurl:example.com
where example.com is your domain name.

you want to look for loads of foreign pages where your url is part of the query string.

there's a long post on this site somewhere about how to stop it. can't remember exactly where, but a search for proxy hijacking should find it (if that's what it turns out to be)