FYI: On Windows 7, you need to press Alt+D to get to the location bar. (I believe that's the case for XP as well.) Ctrl+L doesn't seem to do anything.
Neither Ctrl+L nor Alt+D work for me (Win7 Ultimate, 64bit), but even with clicking manually this is extremely useful for me.
On a different note, back in UNIX land I found myself doing the opposite of what you described: opening the file explorer to the same directory as the command-line. Of course, there is not much to that trick other than choosing an explorer that opens to the working directory or a path provided as an arguement.
On Windows you can also get a nice "browse for folder" dialog in batch files with Wfolder [1]. If you replace "cdwhere.exe" in your script (cdhere.cmd) with "wfolder.exe" [2] and put wfolder.exe in the same directory as cdhere.cmd then instead of going to the location open in the topmost Explorer window the "cdhere" command will ask you where to cd, starting at your current location (like so: http://i.imgur.com/3MCzD4b.png).
Edit: Wfolder comes with a script that's analogous to cdhere.cmd.
[1] http://www.horstmuc.de/wcon.htm
[2] I did it in http://pastebin.com/aq0FiKmz.
Not trying to take anything away from your script, it has a use-case, but just pointing out that there are alternate solutions for systems that don't have your script installed.
cdhere navigates your cmd.exe to wherever the current topmost Explorer window is pointed at.
It's not the same as the OP's trick, of course, but since you're voluntarily using Windows, I'm going to assume you "live" on the command line less than the average UNIX user, and more on GUI tools such as good old Explorer.
https://github.com/eteeselink/cdhere