Mechanical Turk (www.mturk.com)

is a service hosted by Amazon.com. People post simple tasks (called HITs) and then pay others (you) to perform them.

The HITs may be as simple as comparing two items or something more complex, like writing an article. There are always hundreds of HITs available for you to choose from.

The pay is generally pretty low per HIT, but they don't take much time so you can still pick up a fair amount of money if you put your mind to it.