ZXDS is an emulator of Sinclair ZX Spectrum for Nintendo DS, written by Patrik Rak. It is steadily reaching a mature stage of development, and it already has some noteworthy features, like accurate emulation of Spectrum 48k, 128k and Pentagon models (including sound), or support for TAP/TZX/PZX tape files, TRD/SCL disk files and RZX playback files.

Changes:

+ RZX playback (no SZX snapshot support yet, though).
+ Files stored in ZIP archives can be browsed and loaded directly.
+ Support for poke cheats in POK file format, including autoload.
+ Added log screen for better problem diagnostics, especially those RZX related.
+ Turn off the bottom screen backlight after configurable timeout.
+ Automatically save state and enter sleep mode when the lid is closed.
* Alternatively boot from saves/boot.z80 instead of last session state.
* Skip loading of either state upon startup when L/R buttons are held.
* Replaced few busy loops with inactive waits to further improve battery life.
* Improved the last menu action to cycle through all recently used views.
* Extended the range of both AY and speaker samples to make the sound louder.
* Tweaked the Z80 snapshot loading code to support some less conformant files.

Thanks to http://www.1emulation.com for the news.

http://zxds.raxoft.cz/