You need some kind of video editing software that will allow you to import a series of images and output as an avi mpg or whatever. Do a search through the rendering forum and you'll find quite a few articles dealing with this. Here's one to start you off.

https://forum.simplymaya.com/showthre...&threadid=5525

You also might want to check out Mike's freebie render globals video tutorial as I think he demonstrates compiling the video using VideoMach, a free video editor.