Google Earth Mac!
Many Mac users have been waiting with bated breath for the promised Mac version of Google Earth. Now it's here. Just go to the Google Earth home page and click the "Get Google Earth" link to download. And it's free! (Though there are also higher-end versions you have to pay for.)
In case you don't know what I'm talking about: "Google Earth combines satellite imagery, maps and the power of Google Search to put the world's geographic information at your fingertips." (So says the main page.) Among other things, it's a 3D world satellite map that lets you "fly" from one location to another, and zoom in to varying levels of detail, and so on. It's way cool.
Oh, and Google Earth for Windows is officially out of beta today, so those of you who've been using that may want to upgrade to the latest version.
Unfortunately, not all computers have enough processor power or enough graphics capabilities to be able to use Google Earth; check the FAQ for system requirements. (And ignore the sentence that says there's no Mac version.)