TONTO KIDD archives some great old illustrators on his Flickr page. He's Italian so a lot of the work is foreign (and new to me). Unfortunately he doesn't have any sets organized so you just have to flip through and see what you find.
The average-joe quality of these Spidey images kills me…
UPDATE: Tonto-Kidd (Enrico) tells me that he had a Flickr account with over 1,500 images archived before something happened and it was lost. So this is probably a good page to bookmark for more great stuff in the future.