Check out this automated bid sniper. From the pod:

"This program is designed to allow the user to "snipe" at the end of an eBay auction in order to get a better price when other bidders are pushing the price up incrementally. It really doesn't help much when someone else has put in a high proxy bid. What it does do is prevents other users from modifying their bids by bidding right at the end of the auction.

It works out when an auction will end by requesting the information about an item. It looks at the date header sent by the eBay web server and also the end time of the auction. The progam compares the two times and sleeps until "gap" seconds before the end of the auction.

In this way it does not use the host systems time to, only eBay's time."