One tip for finding them through individual publication websites - they are sometimes buried quite deep in the site, and you might find them by searching 'contacts', 'submissions' or 'contributors'.
Worldwide Freelance Writer
Writer’s Digest - You need to type in a search word to bring up related listings.
Jacqui Bennett Writers Bureau - A British site – useful in finding other English-language markets.
Writing-World - Writers Wanted pages by paying and non paying markets.
Drop me a note if you know of other useful sites.
And don't forget to try using online databases for marketing purposes (check my previous post). Most databases include a section called Publications which lists the source from which their archived material comes, and hot links will take you directly to the publication website to find out more about the magazine or journal.