The deals are announced every day at Noon EST/9 AM PST and they only have a limited number of codes. I've seen some deals sell out in less than two minutes and others last all day without getting sold out.
Just go to the Visa Signature Holiday site:
Once there, click on the item you want, enter your Visa card number and they'll give you a unique one-time use code. Enter that code during checkout at Amazon to get your discount.
TODAY'S DISCOUNTS (announced at Noon EST/9 AM PST)
$15 off Super Mario Galaxy 2 - $25.99 after coupon
$20 off Wii Fit Plus with balance board - $69.99 after coupon
Edited by aaronmills, 14 December 2010 - 03:08 PM.
Updated with today's deals