Big topic - heard to begin.
Jack has a good suggestion with MPEG. I like it myself. Another popular one that people use is DivX encoded avi's. Basically you'll use whatever editing software you have to "export" into one of these codecs and formats. Sometimes it can take a *long* time.
Look into creating VCD's for your dad. You can burn them with a standard CD burner and your dad can play it back in a modern DVD player.
Check out
www.vcdhelp.com for info and all the tools.