Thunderbird on Wikipedia
In depth history and information MozillaZine Forums - Thunderbird
Messages about bugs, features, builds, and the program in general. Open Source Articles
Detailed installation guides and tutorials for Thunderbird Thunderbird Portable
Full featured version for portable devices such as USB drives The Rumbling Edge
Weblog about developments in the nightly builds. The Rumbling Edge
Weekly developments in Mozilla Thunderbird builds. BirdieSync
Pocket PC and Smartphone synchronization of cards, events, tasks and mails with Thunderbird, Lightning and Sunbird on ActiveSync and Windows Mobile Device Center. Thunderbird
Official site. Open source cross-platform email and Usenet client based on Mozilla code. Features intelligent spam filters, built-in RSS reader, and quick search. Mozilla.org: Thunderbird 1.0 Email Client Has Landed
Official press release covering the launch of version 1.0. Lightning
Project to provide the functionality of the Sunbird calendar application as a thunderbird extension. Includes download and FAQs. The Mozilla Thunderbird Mail Project
Goal is to produce a cross platform stand alone mail application using the XUL user interface language. Thunderbird Extensions
Extensions are small add-ons that add new functionality to Thunderbird. Thunderbird Themes
Themes are skins that allow you to change the look and feel of the browser and personalize it.