I've never seen these in referral urls but if you have your site listed in Alexa just copy their link to your site and then run it through a server header checker and you'll find a 302 redirect. I did this to all 25 of my clients this morning and found a redirect on every one of them and then bombarded Alexa with requests for them to be removed.
I have written an extensive article on this. Just search for "hijacking web page pr" and my article should come up in first restults. I have 25 clients and deal with this issue constantly. I checked one client's allinurl results this morn and found 4, 302 redirects and wrote them letters. Got one response so far and they are removing the link--so they say.
I don't do this very often however -- puts me in a
VERY bad mood!