You can Google-up plenty with keywords like "wedding video contract".
Also, WEVA (
http://www.weva.com/) has a sample contract.
Some key points to include:
* what happens if wedding is postphoned or cancelled?
* what happens if videographer can't produce the video (camera with tapes stolen, auto accident, couldn't find reception, etc.) - what are the limits of his liability?
* if rate is hourly based, when does the clock start ticking?
* what happens if ceremony/reception take hours longer than planned?
* rights to use shots in your demo video?
* travel fees?
* who keeps raw tapes?
* how long will editing take?
* what happens if editing takes months longer?
* delivery format and quantity?
* do you have the right to designate another videographer?
* state number and type of camcorders, mics, videographers.