hmmm...a pound is 16 oz, the converter (link below) says that would be 3.63 cups of powdered (icing) sugar... I just bought a 2 lb bag of it & split in half between 2 batches...
http://www.traditionaloven.com/conve...r_amounts.html#
the converter also says 1 cup of raw sugar = 2 cups of icing sugar - don't know if that helps at all...
oh - I just googled "powdered sugar converter" to come up with a list of sites to use...