Nice work Blargg! I've been thinking about trying this for quite some time, but never got to it since I've always thought that tricks like this would give too much distorsion and just sound awful. I'm glad you've proved me wrong! :)
If you wanna hear how it sounds on a PAL NES, check out the wavs I recorded at http://www.student.itn.liu.se/~miciw347/