If you are using a Mac try Gawker it will take pictures in intervals with your built in iSight camera and when its done Gawker will put all the pictures in to a Quicktime movie. Examples (Gawker will also let you use multiple webcams)
If you are using a PC download Microsoft's Webcam Timershot. Timershot will save all the photos into a folder of your choosing. To incorporate them into a video drop the pictures into movie maker and see your photos come alive.