Like Oren, I like my MS Keyboard, but I hate it having this useless, oh so very useless, zoom key in the center of it.
I also found out about this hack on how to get the zoom key to be scroll up-down key, but it involves doing xsl work etc.. so this post is for you if you have the MS natural 4000 keyboard and all you want is to have the zoom turned to scroll in less than 1 minute.
Download this zip file that I made.
unzip it into "c:\Program Files\Microsoft IntelliType Pro\"
run the ZoomToScroll.bat file.
you should be done.