Microsoft Mail Beta is Microsoft's brand new web mail service. The product is being built from the ground up based on input and feedback from customers. Microsoft is inviting people from the MSN Messenger beta to join the beta of their brand new web mail service. Testers will be part of the first group outside of the product team to experience the Mail Beta.
A hotmail account is required and is moved over to the new beta automatically. It includes 2GB of space, includes a rich text editor, protection from "phishing" scams and a new easier layout.
News source: Microsoft Connect