Google have confirmed today that they’re aiming to have Mac OSX and Linux versions of their Google Chrome browser ready for release by the middle of 2009. In the meantime, it may be possible to build a version to try out from source. According to the current advisory, they aren’t even working on the user interface yet, so it may not be that functional, but if you like playing with source code (at your own risk, of course), have a look:
MacBuildInstructions – chromium – Google Code – Build instructions for Chromium on Mac OS X