If you're looking for free photo manipulation and digital imaging software similar to Photoshop, then the best one that I have come across is GIMP or GIMPSHOP. You can download them at
www.gimp.org. Its not AS versitile or pwerful as Photoshop, but for the price(free) it's the best out there.
For learning purposes, your friend may want to start out with something a little easier to learn, like Photofiltre(not a typo) to get used to using some of the basic tools and filters. There are also some good morphing and animations software out there that let you use them on a free trial basis.