eBay is rolling out "eBay Calendar Reminders" this week. The new feature allows members to add a reminder to their personal calendar program to alert them when a listing is about to end. Users do not need to be signed in to eBay to use this feature.

Once your reminder is set, you will be notified by your calendar program before the listing ends.

The "Add to Calendar" link is only shown on auction-style and auction-with-Buy It Now listings, and will not be displayed during the last 2 hours of a listing. While eBay introduces the feature to the site, members may sometimes see the "Add to Calendar" link on the Item page, and sometimes they will not.

http://pages.ebay.com/help/buy/calendar.html