UpToDateChromium is a free and simple to use Automator workflow which will allow you to keep Chromium up to date on your Mac.
You can edit the variables at the top of the file if you want to keep the downloads in a different directory.
To install UpToDateChromium as a Snow Leopard service just copy the UpdateChromium.workflow file into the Services subdirectory of ~/Library folder (or /Library for all users).
