CrossOver Chromium runs the Windows version of Chromium natively on both Mac and Linux. Google has plans to support native Mac and Linux versions of Chromium, soon.
CodeWeavers has done this project just as a proof of concept to showcase what Wine can do. Chrome enthusiasts can use this version for now. Wine is an open source technology allowing Windows executables to be run as-if-natively on Intel-based Unix operating systems such as Linux and Mac OS X.
CrossOver Chromium is available as a native Mac .dmg file, or as Linux packages. Mac users can simply drag the .dmg file into their Applications folder. Linux users should use the appropriate tools for their respective Linux distributions to unpack the installer package.