I was updating my webdev powershell script today. I wanted to add support for a -browser switch that would automatically launch a browser window the way chiron from the Silverlight Dynamic Languages SDK. does. I also set the script to serve up the current directory by default. I posted the new version up on my SkyDrive.
While I was working on the script, I thought about how one might shutdown the WebDev server from the command line. That turned out to be much harder. Basically, you have to look thru all the top level windows for one that has "ASP.NET Development Server" in the window text, then you send that window two messages - WM_QUERYENDSESSION and WM_QUIT. Not sure why the WebDev server uses WM_QUERYENDSESSION to shut down it's tray icon, but if you look at WebDev.WebServer.exe in Reflector, you'll see the tray icon form overrides WinProc in order to look for message 0x11, i.e. WM_QUERYENDSESSION.
I threw together a quick little C# console app to shutdown the WebDev server and stuck it up on my SkyDrive as well. Source code is up there too. I had to use a bunch of P/Invokes to make it work, or I would have written it in Powershell or IronPython.
Enjoy.