How to draw a rectangle in PSCS2?

This is obviously a really simple thing to do but I can't figure it out. I have an image on a white background/canvas. Now I want to draw a black (non-filled) rectangle around the image. Also, I want it centred on the image and figure there must be a non-manual way of doing this. I can't figure this out despite consulting my PS books (I think it's too simple a task). How do I do this?!!
DKD

Magic Wand, select the white. Select, invert. Then somewhere is the Stroke command...

Hi, uhh I'm not really sure what you need m8, you might want to try to rexplain or i dont mind if you want to IM me (my AIM icon is right here on the forum under my name on the left)

im a graphics designer and i can probly walk you through w/e you need

if Im thinking correctly, then one way you could do it would be to use the square Marque tool and select the area you want. Make sure you create a new layer- assuming you havent changed keyboard shortcuts hit Shift+F5 on a PC or you can go to Edit>>FIll

choose the color you want the rectagle to be and click ok

now with the marque took select the part of the rectangle you want to get rid of (so that the black rectangle doesnt cover up your photo) and click delete.

hopefully thats what you need...otherwise please let me know

You can either expand the canvas size and change your background colour to black... and if you want, do it again with a larger amount with white to add a white extension with a black frame around the entire original image.

Or, you can select all (CTRL+A) then nudge down and to the right one pixel with the arrow keys, then use the selection menu to modify the selection and contract it the appropriate amount. Then nudge back up and to the left 1px using the arrow keys. (can't contract when entire image is selected so you have to move the selection)

Once you have the selection outlined, you can right click on it and choose the Stroke option, pick your colour and thickness, and you're laughing.

dkd, RAitch's way is the simplest - just expand the canvas using black to your desired thickness. If you want to put a frame line in it then marquee the line, hit add layer, hit fill to the color you want the frame line to be, click select, modify and contract to set the width of the line, then hit cut - fwalah.

Thanks all for your replies. After a flurry of key strokes, backtracks and restarts I have produced a rectangle. Now it's just a matter of whether it can be repeated.
dkd

Select any way you like, edit menu, stroke.