This video really does cover the absolute basics of importing and handling pictures inside iPhoto. A tutorial aimed at absolute beginners. One thing I would say is forget those habits from using Windows! Don't go rooting around in your pictures folder if you are looking for a photo. Use iPhoto for emailing, exporting pictures to disk everything If you really want to get your hands on the actual file itself.

Highlight the picture that you want and then choose File>Export.

[youtube http://www.youtube.com/watch?v=rpz0b21H65s]