You could already root the Droid X with a single click, but now? Now hardly any Android device is immune. Even Froyo-powered phones are falling victim to SuperOneClick. Liberty!
There's still not a comprehensive list of exactly what phones SuperOneClick is compatible with, but the initial word is that it'll root the Nexus One, Motorola Droid, and Samsung Captivate among others. It'll also allow you to side-load apps onto devices—like the HTC Aria—that have been restricted by AT&T. It's currently Windows-only, but expect it to be ported to Mac and Linux before too long. Another caveat: there's no unroot button (yet), so make sure you're sure. And as always, proceed with caution. [XDA Devs via Android Police, thanks Artem!]