Zero is a spectrum emulator written entirely on the .NET platform, using C#, and requires .NET framework 2.0, and now its author, Arjun Nair, has made the source code public and post it on Github.
The philosophy behind Zero is to provide a highly accurate emulation of the various Spectrum models while also providing a nice, user friendly experience.
Arjun said in his post that he still didn’t decide on a license, but his idea it will be something along the lines “do as you will but please credit” for now. He will update the license as soon as possible.
Link: Github
Source: World of Spectrum Forums