Ixus does not have 3:2 format.
Rexlim, does DSCN prints fit in a photo album for 4R?
To avoid having important details chopped off by the photo print shop, I usually crop the pictures in Photoshop. I always ask myself too why most cameras manufacturers don't have the 3:2 format. (The old Casio EX-Z4 has, and the new Panasonic FX9 too).
Now, there's no way to print a 3:2 image on a 4:3 paper. I am thinking to work around it by blackening out the top and bottom of my digicam LCD so that I capture details within what will appear on a 4:3 paper after cropping by the print shop.