<p>This wonderful email client, calendar, and groupware application not only looks like Outlook, it also matches Microsoft&#39;s email program in features and functionality.</p><p>Mozilla Thunderbird is a fully featured, secure and very functional email client and RSS feed reader. It lets you handle mail efficiently and with style, and Mozilla Thunderbird filters away junk mail too.</p><p>Integrated with the nice KDE desktop, KMail is powerful but easy to learn use, especially if you&#39;re coming from Windows.</p><p>Balsa is part of the Gnome desktop environment (which is just as nice as KDE), but it does not yet equal KMail in advanced features.</p><p>Sylpheed is a friendly email client with a particularly easy to use interface. There are a few things that Sylpheed does better than Balsa, and a few more where Balsa has an advantage.</p><p>Alpine is powerful console email program that makes you use email productively with automation aplenty and nary a distraction.</p>