For those of you who used the VSEdit Powertoy for VS 2003, you’ll be happy to know that you can have similar behavior in VS 2005!
Just run “devenv.exe /edit <filename>” from the command line to open any file in an existing instance of Visual Studio 2005.
You may want to create a VSEdit command if you find yourself using this feature a lot. Just create a file called "VSEdit.cmd" (you can use notepad to do this) with the following:
@"%Program Files%\Microsoft Visual Studio 8\Common7\IDE\devenv.exe" /edit %*
Also, place VSEdit.cmd in a directory that’s in your PATH (or add the directory to your PATH).
now you can do vsedit <filename>