Thunderbird 3.1 beta 2

* New quick filter toolbar.
* New migration assistant.
* Improved support for Personas.
* Several fixes to improve upgrading from Thunderbird 2.
* Several design improvements and corrections to the interface.
* Stability and memory improvements.

Download page:
Code:
http://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/3.1b2-candidates/build2/win32/en-US/