Do a search in Google for your domain www.yourdomain.com then mouse over it, if the url is not yours then bingo it’s hijack or an accidental 302.

If you are really worried about people hi-jacking your website then you could write a small script that captures the referrer and does a header check … if the header check returns a 302 .. panic .. run around the room for awhile then sit down… you where clever enough to find the 302, you should be clever enough to combat it..

1) Find whois info … email them tell them that they are cheap robbing gits and remove the 302..
2) False Whois .. report them to registrar and there host and to make sure you tell all your friends just in case it’s one of your friends ( best do friends first)
3) All else fails 302 them back, now it’s the national lottery ;)

but you only have a small window of opportunity, so acted quickly most ISP will have the information on the domain get to them, they hate been woke up and tend to remove after asking few questions.

here are a couple of threads about hi-jacking

SearchEngine Watch
Threadwatch
DaveN