You need an Intel Mac running Mac OS X 10.5 (“Leopard”). If you want to take Chrome for Mac for a spin you can download (old version OR new versions) the application I have compiled. Opera never caught the fancy of web developers, but chrome has generated tremendous interest among mac users and is poised to capture some market share when it is polished and ready. Finally Firefox and Safari has some real competition on OS X. It also beats the latest Firefox 3.1 Beta 3 scores on windows. On SunSpider benchmark the latest chrome build is far ahead of Firefox 3.0 and slightly ahead of Safari 4 Beta. A cold start is blindingly fast and web sites load quickly. Chrome hasn't lost any of its speed in its port to OS X. It also adheres to the Mac design principles with the menu bar on top unlike its windows cousin.
Chrome on mac works similar to the one on windows, with one process spawned per tab, which you can monitor using Activity Monitor. While it is far from stable and ready for daily use, it is stable enough for the Chrome Developers to use it to dogfood basic browser functionality.
Google Chrome can now be built and used natively on Mac OS X. Download Native Google Chrome For Mac OS X