decompiler - a general purpose decompiler.

Decompiler is a C# project containing a decompiler for machine code
binaries.  This project is freely available under the GNU General
Public License.

The project consists of front ends, core decompiler engine, and back
ends to help it achieve its goals.  A command-line, a Windows GUI,
and a ASP.NET front end exist at the time of writing.  The decompiler
engine receives inputs from the front ends in the form of either
individual executable files or decompiler project files. Decompiler
project files contain additional information about a binary file,
helpful to the decompilation process or for formatting the output.
The decompiler engine then proceeds to analyze the source code.

Please note that many software licenses prohibit decompilation or
other reverse engineering of their machine code binaries. Use this
decompiler only if you have legal rights to decompiler the binary
(for instance if the binary is your own.)