The Explorer extension the framework installs to view the GAC
You can also map a drive directly to your GAC and then you'll be able to see the actual directory structure.
Go into command prompt and type: subst z: %windir%\assembly\gac
I got this info from http://weblogs.asp.net/jkey/archive/2003/02/25/3006.aspx
-------------------------ONE MORE WAY-----------------------------------------
1. Open Regedit, browse to HKLM\Software\Microsoft\Fusion.
2. Add a REG_DWORD value named 'DisableCacheViewer'; set it to 1
3. Open an Explorer window and type in C:\WINDOWS\assembly\GAC_MSIL\
