Exiftool
Exiftool is a great commandline tool. It isn't written by me at all, but I like to use it to be able to do batch-operations on the meta-data embedded in images.
Here is the procedure to install it:
Download exiftool:
Download-page: http://www.sno.phy.queensu.ca/~phil/exiftool/
Choose version "Windows executable"
Save this file to a folder you choose, I save such things in a folder named "C:\Programs\Exiftool\", and if you do as well, then you needn't change the script that follows...
Unzip the contents of the zip file to the folder "C:\Programs\ExifTool\"
Rename the file "exiftool(k).exe" to "exiftool.exe"
There are help pages on it's website explaining the possibilities, and the tool can do a lot of things, but it is not always easy to find the exact syntax to let it do what you want. I created some scripts over the past months to help out other people, and they are found on other pages on this site... just browse around and you'll find them...