I know I'm very late posting this, but since this is so significant (and I happen to have a slight bit of free time right now), I wanted to post the news here.
For anyone who may be unaware, Firefox is basically a stand-alone version of Mozilla's web browser. However, Firefox has been greatly enhanced, supports a ton of useful new features, and can be easity extended with any of the hundreds of extensions and plugins available for it.
Similar to Firefox, Thunderbird is the stand-alone version of Mozilla's mail client and address book. It has also been greatly enhanced, and is officially (by my standards) one slick e-mail client.
Here's a compilation of useful links for both Firefox and Thunderbird. If you haven't tried either Firefox or Thunderbird yet, please give it a shot. Trust me, give it one week, and you'll be thanking me for turning you on to it.