Oh, but it's not an outlook express account, OE is the program you use to check the mail, the account is with the company that provides the email.
Also, as default OE downloads the mail from the mail server and then deletes it from the server, once it is deleted from the server the only copy of that mail is in your outlook express, so you can check mails on the phone before you get them in OE, but after you've got them in OE you can no longer look at them from any other computer or device.