Is it ok if i take a pic off of Google images and use it as a pic on a facebook fan page?

[Kay]

You don't own the picture, and if it's not yours and you don't have permission from the owner to use it, you're violating the copyright of the owner.

http://www.law.duke.edu/cspd/comics/zoomcomic.html
http://www.copyright.gov
http://www.photosecrets.com/tips.copyright.html

Most people are quite gracious about granting permission for non-revenue generating uses, and many are equally adamant that you take something down that you don't have permission for. Ask me before you use something, and I'll probably tell you it's fine to use my work. Don't ask me, and I'll come after you like a ton of bricks.