Google sets deadline for Chrome on Mac, Linux
If you're interested, you can follow Google's Mac build instructions and see how the project is taking shape. You'll also need XCode 3.1 and gclient. More detailed notes on the Mac project area available on the following Chromium Dev page.
While the news is bound to make many Mac users happy, many commenters aren't happy with the announcement that Chrome won't run on OS X 10.4 and that PowerPC support is not planned, at least for now.
The Linux port appears to have taken a back seat - the project page hasn't been updated since November 18, 2008. Linux build instructions were, however, updated last week though page clearly states that there is "no working Chromium based browser on Linux."