Wired has a first look at the Kindle for Mac release.

Amazon has at last released Kindle for Mac, which means you can now read your Kindle books on most any device. It joins the iPhone, PC Blackberry and, of course, the Kindle itself. Like the PC version, Kindle for Mac is a bare-bones reader. You turn pages with either the scroll-wheel of your mouse or the arrow keys, and it stays in sync with any other device authorized for the same account. You can view notes and bookmarks made on other devices, but you can’t create new ones (a limitation shared with the PC version). – From Wired