I agree with all of the comments above. You can also find a lot of good advice at this web site: http://digital-photography-school.com/wedding-photography-21-tips-for-for-amateur-wedding-photographers

Good luck on the day.

I had so much fun looking though past entries in this forum I just had to join. You guys and gals make this a great site, and many of the photos are sensational!
I'm 75, long time amateur photographer (since 1960ish). Was once a strictly 120 film man (6x6 and 6x9). Twin lens reflex: Rollie and Mamyia; Press Mamyia for 6x9. Weston Master V of course. (Old guys will know what I am talking about!) Was a member of photographic clubs until I had a stroke. Now I shake so much I had to switch to digital and fumble with the menus. My wife told me to use all settings on auto and stop getting stressed. So here I am with a Panasonic bridge camera and keeping it simple but happy.