With the Treo Mail service installed, your communicator can check your mail manually or automatically at an interval you specify. You can have the service notify you as soon as a new message is available. You can control which messages get delivered to your communicator by setting Treo Mail filters. In short, with Treo Mail, your communicator gains almost all the wireless email capabilities of a BlackBerry, along with all the other Treo advantages.

How does Treo Mail work?
Treo Mail comes in two varieties. Treo Mail Corporate Desktop Edition is for people who get their mail from a Microsoft Exchange email server (or even a POP3 server) behind a corporate firewall. Treo Mail Internet Edition is for people who use a POP3 email server connected to the Internet. That covers most home users, except for those folks who use AOL, Excite, Hotmail, Juno, or Netscape mail. I used the Internet Edition for this review, with Access-4-Free (they provide 10 free hours of connect time a month) providing the POP3 email service.

The key to understanding this product is the Treo Mail Service Operations Center. The Operations Center receives email from your PC (Corporate Desktop Edition) or POP3 email server (Internet Edition). The Operations Center's servers store an encrypted copy of your email, delivering it to your communicator when requested. The Operations Center can also send SMS alerts to your Treo when it receives new email for you. You control the Treo Mail Service Operations Center through a set of secure Web pages provided by the service.

The Operations Center interacts with the Treo Mail Application on your communicator. The Treo Mail application is a standard email program, allowing you to send, receive and forward messages.

You control several aspects of the Treo Mail Service from the Treo Mail Application, including how frequently the service delivers email to your Communicator, and which types of email will be delivered.

The difference between the Internet Edition and Enterprise Desktop Edition is a result of the different ways Microsoft Exchange and POP3 email servers work. In the Internet Edition, the Treo Mail Service Operations Center gets your email directly from the POP3 email server. However, due to limitations in the POP3 standard, when you read or delete email on your Treo, there's no way to mark that message as read on the POP3 server. This can be a bit confusing and requires you to do more work.