Google is now offering a beta version of Gears for Safari.
Gears is an open source project that enables more powerful web applications by adding new features to your web browser, such as:
• Let web applications interact naturally with your desktop
• Store data locally in a fully-searchable database
– This is BETA, it is not an official release, it might break your browser. Chances are it will break your browser. Please proceed with caution.
– Minimum system requirements: Safari 3.1.1 on Tiger 10.4.11 or Leopard 10.5.3.
– Make sure you have Gears 0.4.16.0 before you file bugs. You can check your version on http://gears.google.com.
– You can see a list of known bugs at: http://code.google.com/p/gears/issues/list?can=2&q=Safari
– New bugs can be filed on our public tracker at: http://code.google.com/p/gears/issues/list
– This version will autoupdate.
More info and download link here.