Auction Informant

From HammerTap:

Auction Informant monitors the items you (or any seller) are selling on eBay. When a new item is posted, or an item receives a bid or a bid retraction, the program will send an email message alerting you. It can even send messages to your wireless phone or pager. The program can monitor the accounts of many sellers simultaneously, and send messages to many email addresses. Always know when new items are posted or bids are placed. This application works quietly in the background from the system tray, and updates itself automatically from the internet when a new version is available.