WideMail (was WidescreenMailPlugin) is a plugin for Mail.app for Mac OS X 10.5 Leopard which turns the message view from a two-row horizontal view, to a two-column vertical view.

What’s new in this version:

Version 0.1.2:

* Added: Defaults preferences to set various options.
* Added: WideMailPrefs application in the dmg for user friendly setting of defaults.
* Added: Relative date formats for “Today” and “Yesterday”.
* Fixed: Second row in WideMail Column does not change text color when row is selected and therefore is hard to read.

Website
Download WideMail