Xpectroid is a ZX Spectrum 48K, 128K, Plus2, Plus2A, Plus3 emulator derived from GP2xpectrum by Hermes/PS2Reality and continued by Metalbrain, Seleuco & SplinterGU. iXpectrum latest release can be easily installed from Cydia. Xpectroid latest release can be easily installed from Android Market.

http://code.google.com/p/xpectrum/