via http://www.aep-emu.de/

Marat Fayzullin has ported his (free) Spectrum emulator Speccy to the Android platform: Speccy for Android

Quote:
New in 1.7.21:
  • No longer showing AdMob ads.
  • No longer showing ads if you have bought at least one of my paid apps.
  • Worked around an Android bug that prevented some ZIP files from opening.
  • Added third virtual fire button and assigned it to fast-forwarding everywhere.
  • Arranged fire buttons vertically in landscape mode.
  • Moved joypad away from the bottom-left corner button in the portrait mode.
  • Added multiple Freeze/Restore slots.