PowerSnipe eBay Auction Sniper lets you cheat to win an eBay auction. These snipers are applications (either desktop or web apps) that automatically bid for you at the latest possible moment. Thus, you don't give your competing bidders to outbid you. This app works with an online service, which isn't free. You pay per month, and the bidding is done from their servers, which means that you don't have to have your computer on all day just for that one auction you want to win.
The desktop application is very simple. It consists of two tabs. The first one gives you an access to your PowerSnipe online account and you can also change snipping options from there. The second tab is an auction browser, which basically consists of a built-in web browser. You can use it to search for anything on eBay. Once you have found the auction that you want to snipe, you can click on the "Snipe" button, which will add the auction to your online account and let you change how much money you want to pay for the item (max bid) and when to snipe.
As I mentioned above, the main advantage in using this online service is that all you need to do is set some settings and the PowerSnipe servers will take care of the rest. Keep in mind that they will have your eBay account settings and login details.