esniper, not esniper.com. A free (open source) program. (That's right, I am all for free software, long live Debian!) You can set it up to bid how you want. I know a lot of people like the .com services, but I don't understand that when you can have the same thing on your own computer doing what you want, when you want.
And sniping is fun. You put in your highest bid. Watch the auction with a couple of seconds left and see if your highest was the highest. I get all tingly inside with anticipation.