One can order Japanese import video games from Nation Console Support, Inc.. They've always provided me with good service, and I recommend them, even though their page always seems to be a little out of date. A lot of their stock isn't even posted; you just have to e-mail them and ask if they have whatever you're looking for. If anyone knows of any other good Japanese game importers, please let me know and I will post links here.

For all your emulation needs, go to Zophar's Domain, which is probably the best emulation site around. Their news staff does a terrific job, and they have just about every emulator there is available for download. If you're looking for ROM images, there're tons of ROM sites listed on their Links page. It's much less frustrating than just using a search engine.