You should have gotten something like this (same thing, but with the basic america wall hookup instead... i could only find a photo of whatever place this is for)
http://mactips.info/tips/wp-content/uploads/2007/08/out-of-the-box-9698.jpg
You can either attach the powerbrick directly into the wall, or you can swap out the corner piece with another 6 foot ? (not sure how long it is) cord like in the photo.... you should have gotten these cords with your computer.
If you don't mean that... then i guess just an extension cord.