There was another one shortly after Dale who would tell peole that he was a recruiter for a big name studio. He would get people to send him pics of their work then about a week or so later, tell them that the Art Director was interested and wanted to see the actual models to see how they were being built. So the idiots would send him their raw files and this kid would come back a while later again and tell them that they didn't get the job. Then he would change things on the model and put them out as his own.
But to address your issue, DW... If you're only putting the models on your website, the best thing to do is just put in a caption somewhere who the original artist was and give a link to his website or the page you got it from. As for using images of items that are genereally public (like planes, helicopters, cars, etc) unless you want to credit Lockheed MArtin or Sikorsky, I don't think that's totally necessary.
Bottom line is, if someone else thought of it first, make sure you mention it.
Dave Baer
Professor of Digital Arts
Digital Media Arts College
Boca Raton, Florida
dbaer@dmac.edu