Developers who are actively testing the latest incarnation of Mac OS X were greeted with an update today. Build 10A421 of Mac OS X Snow Leopard comes just 10 days after the previous release and comes as a 741MB download.

In the Software Update utility Apple describes the update as:

This Snow Leopard Developer Preview Update is recommended for all users running the Snow Leopard Developer Preview Build 10A411 or later. This update includes general operating system fixes for stability, compatibility, and security.

Mac OS X Snow Leopard will be available to the public in September, existing Mac OS X Leopard owners will be able to upgrade for just $29.