It automatically displays all of the items that you are watching in MyEbay, giving you information on each item including the time left. It will bid for you a few seconds before the end of an auction according to your instructions.
Getting more detail on eBay sellers and auctions view it
How to bid on and win your auctions view it
Learning how to sell your stuff on eBay view it
Getting your items listed and sold on eBay view it
Searching for and finding stuff on eBay view it