In the age of Twitter, SMS and IM is e-mail obsolete? Not yet. Like it or not, most of us gets dozens, even hundreds, of e-mails a day. Since that's \n\nthe case, why not look for the easiest and least costly way to manage that flood of useful\u2014and useless\u2014 information?The hands-down answer to that question is the latest version of Mozilla Thunderbird, the open source e-mail client brought to you by the same folks \n\nwho develop and support Mozilla Firefox, the world's number two Web browser. Thunderbird does pretty much everything and then some that you can \n\ndo with Yahoo mail or Gmail (with the exception of Google's new Buzz social networking tool) and lets you keep email on your own hard drive and \n\nunder your own control. I'll make a quick confession here. I'm partial to open source software because it benefits from the labor and love of a huge community of developers \n\nand users, and it's not the product of a huge corporate monolith whose name begins with "M." While open source software isn't necessarily free, \n\nThunderbird is, and it will run on Windows, Mac or Linux-based PCs. Before I tell you more about why I think Thunderbird is such a good choice, I should tell you when it isn't. Thunderbird supports POP3 and IMAP \n\nmail systems, but not Microsoft Exchange. So if your job requires you to use Exchange, T-Bird isn't for you.Light on its FeetAfter cooking for more than a year, Thunderbird version 3 debuted a few months ago with a host of new features and a better, more streamlined \n\nlook. The first thing you'll notice about T-Bird is how little time it takes to download and install. That's because it's a pretty svelte bit of code, especially \n\ncompared to Microsoft's bloated Outlook e-mail program. The next thing you'll notice: Thunderbird looks more like Firefox than ever. The developers have added browser-like tabs to the interface. Click on \n\nan e-mail in one of your mailboxes and it will open up in a tab, an improvement that it makes it much easier to keep track of what you're doing. For \n\nsome reason, though, e-mails you are composing show up on the usual program button on the bottom of the Windows desktop, but not on a tab. \n\nMozilla should fix that. Find that NeedleWhen it comes to giving you the ability to organize and search e-mail, T-Bird really stands out. Understand that T-Bird lets you set up multiple \n\ne-mail accounts. For example, I use three separate email addresses: one for Yahoo mail, another related to a publication I write for and a third based on \n\nmy personal domain. Mail from all or any of those accounts is downloaded by clicking a "get mail" button and the messages appear in folders dedicated \n\nto each account. This couldn't be more simple. It's worth noting that you can funnel multiple accounts into Gmail, as well. But T-Bird's interface wins out. Once you've downloaded your mail, T-Bird makes it easy to set up the usual nested folders and move stuff via drag and drop or by using a pull \n\ndown menu. I don't understand why Gmail has moved to the label metaphor. To me, it's a bit confusing; and doesn't touch the folder metaphor when it \n\ncomes to seeing your mail at a glance. Yahoo mail does allow you to create folders, but the interface is cluttered up with ads and tools for chats and IMs, and there's no drop and drag. \n\nFolders are very useful, but until now, searching for mail in Thunderbird was awkward since it had to be done one folder at a time. But T-Bird 3 has \n\nadded global search, and a good set of search filters. Results open in a separate tab and give you several useful views of the results. Some users on the Mozilla discussion boards say that if your folders \n\nare very large, global search is annoyingly slow. If that's the case, it can easily be turned off. Another feature I really like is the attachment reminder. How often have you sent an email to someone and they reply: "But where's the attachment \n\nyou promised?" If you type the word "attachment" in the text, you'll get a reminder to actually, well, attach it. Pretty cool. The bottom line: T-Bird 3 is fast, easy to use, and a much better tool for organizing your e-mail than anything Yahoo or Google have to offer. San Francisco journalist Bill Snyder writes frequently about business and technology. He welcomes your comments and suggestions. Reach \n\nhim at email@example.com.Follow everything from CIO.com on Twitter @CIOonline.