Mozilla's Thunderbird is a stand alone email client. It is available for Windows and Linux machines. It's open source, and although Thunderbird alone only downloads email, the Lightening add-on turns Thunderbird into a great calendar and scheduling application as well. Other add-ons add functionality like: multiple language spelling dictionaries, contact syncing, the ability to synchronize with your cell phone. There's even an add-on which lets you use Thunderbird as a VOIP client, similar to Skype. Change the look and feel of Thunderbird with skins or themes.
Just like with any other software, some Thunderbird add-ons and themes aren't designed to run with Linux. Be sure to read the system requirements and documentation before you download. This does bring up one great feature of the open source system, though. If you find an add-on, plug in, or theme you want, but it's not compatible with Linux, take the time to email the developer and request a version for the Linux platform. Linux is growing in popularity, but the developers don't know what Linux users want unless we ask.
Thunderbird downloads quickly, and is easy to configure. The application supports multiple email accounts, as well as newsgroups, RSS News and Blogs, Unix Mailspool, and auto configuration for Gmail.
Mozilla programmers believe in giving the user control over all settings. You can configure disk space, spam filters, return receipts and security settings with just a few clicks.
For me, Thunderbird's best feature is the ability to sync Google Calendar and Remember The Milk task manager service with Lightening. No other email and calendar program I've tried combines those two services as seamlessly.
In this series, we'll explore how to install and set up Thunderbird, find, install and configure add-ons, hacks & tips specific to Ubuntu Linux, and even how to develop and submit your own add-ons.