Use PowerShell to view contents of the Global Assembly Cache (GAC)
Another option is that the PowerShell Community Extensions installs a GAC provider, so you can do this:
dir gac:If you are on PowerShell V2, be sure to grab the 1.2 Beta.
As stated in the docs:
Starting with the .NET Framework 4, the default location for the global assembly cache is %windir%\Microsoft.NET\assembly. In earlier versions of the .NET Framework, the default location is %windir%\assembly.
You may want to search in the appropriate subdir or even in both of them.
To list entries in the GAC;
gacutil -lIn powershell you could parse the text output of the above.I don't know of a managed interface to inspect the GAC.