HI all!
i have the same problem. i used to work for a dc in greece last summer (2007) as a photographer, quit after the season for commission reasons and now i find some of my best pics on their site. it used to be just a handful, but now they redesigned and its about 20. no mention of my name. they didn´t even erase the copyright notice i put at the bottom of each pic. on the site, it´s not readable because of the resolution, but i recognize it. i have had these pics (or some of them) on my flickr acc, as copyrighted for some time. is there anything i can do? i know if i contact them, they´ll ignore me, because without those, they wouldn´t have any decent pics to put on their site. and being greeks, the idea of paying me for the licence would be ridiculous to them. not being paid adequately was my reason for quitting in the fist place. they didn´t even ASK if they could use them ffs 
angry hellas
/edit: websites to prove it:
my image on flickr: click me
their website: click again (select diving sites>discover scuba.) all 8 of these are mine(and more on the site), see the one with the bubbles?