Where can I download cs2php?
Whole package including translator, web server for testing C# code and other libraries is available on GitHub.
Why cs2php compiler is available only on source code?
Binary version is currently not distributed. Cs2php depends on Microsoft Roslyn and Roslyn license doesn’t allow to distribute Roslyn binaries.
Note: The current license is for evaluation and preview purposes only and does not allow redistribution of the Roslyn binaries. Sharing of sample projects built on the Roslyn APIs is permitted, but sample users must have either the Roslyn CTP or the Roslyn NuGet package installed in order to build and run.
You have do download and build cs2php compiler by yourself. Source code is available on GitHub.