N64oid is the Nintendo 64 emulator optimized for Android, developed by Yongzh, who is behind NESoid, SNESoid, GameBoid, Ataroid, and more (!).
N64oid has the option of using hardware keys or an on-screen gamepad. Gaming with an on-screen controller is nothing like the real thing; it works, but pulling off combos, like those required in fighting games, isn't easy. There's an option to use your Android device's accelerometer as the N64's analog stick, however, which could make RPGs like Zelda a lot easier to play.
As far as finding games to play with N64oid, if you still have your old N64 cartridges, you can find ROM backups with a quick Google search.
- Run most games smoothly at a reasonable speed (if not full speed) with sound. This requires you have a high-end device (Nexus-S, Nexus-One, Droid, Samsung Galaxy, etc).
- Save/load game states at ANY points, as well as the in-game save support (SRAM, EEPROM, etc).
- A configurable, translucent on-screen keypad that is very easy to use.
- Key mappings to map game keys to hardware buttons.
- Option to use the G-sensor as the analog stick.
- A variety of settings that you can tune on your needs.
Also, Yongzh's emulators have been downloaded around 5 million times, so the on-screen gamepad is obviously not that bad.
Download From: Android Market ($5.99)