Installed on the menu bar for a quick and clean access.
Google Docs Sync for Mac OS X allows you to synchronize your Google Docs files with a folder in your HDD. All your changes in your files are synchronized to Google, and all your changes in Google files are done in your local HDD.
Can't be easier. Can't be more useful.
Requirements: Compatible Mac OS X Lion. Requires any Google Docs or Google Apps account.