[H] Iphone 4 power

[Winterlight]

I am gifting someone a Kindle Paperwhite. These don't come with any 
kind of charger but uses a standard USB port and charge supply. The 
recipient of the KindleWhite has a Iphone 4S and a Powerbook 
laptop... so is this going to work OK. So will they be able to charge 
the Kindle using the Iphone power wart and a USB cable? thanks
w