POP3 Simple Migration Guide
This step-by-step guide is found in the PDF attachment of this post. Click on the title of this post to get to the attachment.
In order to trial* Microsoft Exchange Online you will need to activate the trial version of the Microsoft Business Productivity Online Standard Suite. While this guide will help users from any platform to activate the trial, add users, set up their domains, and migrate any data, it's instructions are a bit simplified for POP3/IMAP users who typically do not set up e.g. directory sync. Please see Microsoft Online Services TechCenter for additional resources.
*NOTE: The trial provides the FULL Microsoft Online Experience. Once you are happy with the trial, it is a simple matter to change the trial license to a paid subscription of the entire suite or to just one service (eg Microsoft Exchange Standard) without losing any of your data or impacting your use.