you could use the rectangular selection tool on an empty layer and then select edit > stroke that should do it.
Thanks, Ben. That did it. BTW, you have to select "center" or "inside". It won't show up if you select "outside".
I just tend to select the rectangle then do Modify --> Border and set the border width. Then you just fill it black.
Not sure which program you are referring to, but I was asking how to do it in Photoshop 7, and there is no menu category entitled "Modify". There is in Fireworks, but there is no "border" to select in Fireworks under that menu category, at least not in MX. Thanks, though.