to open (File-)Explorer in the folder of your current solution
click menu 'Tools' - 'External Tools...'
and fill in the following parameters...
in Visual Studio 2003
Title: Xplore Sol&ution
Pay attention to the 'Arguments'-section
as this does NOT work in Visual Studio 2005
Visual Studio 2005 appends a backslash to the resolved $(SolutionDir)..!(?)
Read as: on my system is does :-(
So 'myDrive:\Folder\SolutionFolder\' becomes 'myDrive:\Folder\SolutionFolder\\
(My) WORKAROUND: supply 'Arguments' as
Again pay attention to the extra \. after $(SolutionDir)
This 'tricks' Visual Studio and/or '(File-)Explorer to use 'myDrive:\Folder\SolutionFolder\.\', which is a valid path :-)