i know they make a tool for wood that makes square holes. is there a tool or a method to make 'em in sheetmetal?

Do a web search on Roper Whitney. They make sheetmetal punches and you can buy the stamp for sqaure holes

i cant remeber where, but, i just saw a square hole maker....i've alway drilled a hole the size i wanted and used a file to make the corners, which is fine if you only have a couple to do..an air file helps big time in this case also

We've got a Greenlee set of round knockout punches but only for round. They make square ones but unless you've got a lot to do they're a little pricey. You can prolly find 'em cheaper.
http://www.electricsupplyonline.com/prod/greenlee-knockouts.php

thank you all very much for your help.
rob