Mozilla has made the Thunderbird 3.0 Release Candidate available for download. This is a public preview release intended for developer testing and community feedback. According to Mozilla, it includes many new features as well as improvements to performance, web compatibility, and speed.

New features in Thunderbird 3 that require feedback include:

- New Search Tools
- Tabbed Email
- Message Archiving
- New Mail Account Setup Wizard
- Improvements for Developers

The complete changelog for this release is available here

Testers can download Thunderbird 3.0 Release Candidate builds for Windows, Mac OS X, and Linux in 49 different languages.