Thunderbird 3 beta 4 available for download

Mozilla's popular email client 'Thunderbird' is progressing nicely, having hit the beta 4 milestone of version 3 just earlier, bringing some nice new changes and improvements with it according to the guys over at ghacks. The release brings a few new optimization features, including support for Windows Vista's search and better Gmail integration.

Some of the improvements, as listed by Mozilla, can be found below:

New Search with Advanced Filtering Tools:
Search results now include advanced filtering tools. You have the option to filter your results by sender, tag, attachments, people, folder, and mailing list. You can also filter your email using the timeline tool.
New Global Search Field with Autocomplete:
When typing in the Global Search field, Thunderbird autocompletes against your address book. You have the option of searching everywhere or filtering against different parts of the email such as by subject or by sender.
Redesigned Mail Toolbar:
The Mail Toolbar is redesigned to include the new Global Search bar. Buttons such as reply, forward, delete, junk are part of each email message. You can add those buttons back to the main toolbar by customizing the toolbar.
Smart Folders:
The folder pane offers a Smart Folders mode which combines special mailboxes, like Inbox, from multiple accounts. Smart Folders is now on by default.
Improved Gmail Integration:
Better recognition and integration of Gmail's special folders such as Sent and Trash including non-English versions of Gmail. Thunderbird also uses All Mail as the Archives folder.
For Windows Vista users, Thunderbird 3 is now integrated with Vista search results. On first start, Thunderbird will prompt to install its indexing system into Windows Vista and you can choose to see Thunderbird email and news messages in Windows search results.
For Mac users, Thunderbird 3 can import from Mail.app, read your OS X address book, and use Growl for new mail alerts.

These are all excellent improvements, and will certainly help Thunderbird in becoming an even bigger competitor to its rivals. If you want to try out the fourth beta, you can find download links below, directly from Mozilla.

Download: Thunderbird 3 B4 for Windows.
Download: Thunderbird 3 B4 for Mac OS X.
Download: Thunderbird 3 B4 for Linux.