I know there is a small utility program to do this, but my memory fails me. I often want to find the location of an executable that is somewhere on my windows path -- I just don't know where. I know it is on my path because I can run it regardless of my current directory. Can someone refresh my recollection? :-)
There is a good answer for this in PowerShell over on StackOverflow
https://stackoverflow.com/questions/63805/equivalent-of-nix-which-command-in-powershell
The command you are looking for is a port of the whereis command available under UNIX based operating systems, there is a project available on CodeProject, a batch file and a downloadable utility. Take your pick