http://replymanager.com/ - Reply Manager is an email management tool that is entirely web based. It was created to make it easy for eBay sellers and online stores manage high volumes of incoming mail.

Reply Manager works with multiple channels, like POP3, IMAP, and eBay's API. Using it, you will be able to automate email and respond credibly and quickly. You will be able to easily stay organized thanks to the reports as well.