This is pretty nice. Google just announced a new feature called 'Preview Pane' in Gmail (including Google Apps users).
The feature does just like it sounds. It allows you to preview your mail in a horizontal fashion. This is a really smart move, as it enables you to use a wide-screen monitor more effectively.

As a side-note, this is somewhat similar to what Mail.App in OS X Lion.
What do you think? Do you prefer the old style, or this new view?