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 1.7.23:
  • Added menu option to invoke built-in debugger.
  • Added menu options to rewind, start, and stop tape.
  • Added Japanese and Russian translations.
  • Added configurable frame skip setting.
  • Enabled browsing from the file system root.