Here are some links that discuss animating your presentation in Power Point.

http://www.presentationhelpdesk.com/killer-animation-slides-for-powerpoint.html

http://office.microsoft.com/en-us/powerpoint-help/animate-your-powerpoint-web-presentation-HA001045111.aspx

Here is a great website to get animated clip art.

http://www.animationfactory.com/en/