Overall, it's a nice emulator. Just a few problems, though:
1. It sucks 100% CPU even when it's not doing anything at all (i.e. before you open a ROM, or if you switch to another application).
2. Seems to have somewhat high system reqs - with my P3 933, it skips frequently (this may be due to #1; then again, my own emulator has even higher system requirements).
3. I noticed you have per-tile PPU emulation (similar to what my emulator does), though you've got a minor bug with setting the VRAM address via $2006 - you currently allow setting the VRAM address above $3FFF (normally, the first write always clears the upper 2 bits).
4. Noise doesn't sound quite right; maybe it's just that it's really loud.
Is there any documentation available for this emu?
P.S. If you don't get this note, let me know and I'll write you another.