The Thunderbird 2.0 e-mail application, release candidate 1 (RC1), has been posted by Mozilla.org.
Thunderbird is an open source, cross-platform e-mail program available for Mac OS X, Linux and Windows. The final release of version 2.0 is expected by the end of April.
Thunderbird 2.0 is a Universal Application, requires Mac OS X 10.2.x or later and is free.
Thunderbird 2.0 RC1