I ran accross a post a few months ago about this.
Simply, you create a basic Snapfish (or whatever you use) account, and then print a card and give it to your guests with the account info. Ask them to upload all their digital images from the wedding.
Everyone can see everyone else's pictures, order whatever they want and pay for it themselves. This won't include the professional photography-just anyone who shows up with their camera.
Plus, you get to see all the pics from ALL the angles.
Are you doing this? How?