New Yahoo!Mail which is in it’s beta version is much like Outlook Express. It is divided into three sections: Folders, Email Headers, and Preview Pane. Once you click on the email title it will automatically load the email into the preview pane. Everything is very easy and fast now; compose, reply, and attachements are done on the fly, as opposed to reloading the whole page previously.
~A note of caution, the Mail Beta still incomplete. You will find some missing features and some additional issues with fetching some emails. I’ve had to completely reload the browser page sometimes in order to resold the issue. AND THERE IS NO EASY WAY TO CONTACT SUPPORT ON ANY ISSUES YOU MAY COME ACROSS.
If you want to try it out for yourself, you can sign up for it here.