Domain Access 6.x-2.2 was released yesterday. This is the last 6.x release, further development will go into 7.x branch.

Things to be aware of from a developer perspective:

• Change to hook_domainwarnings() - http://drupal.org/node/692772. Won't break existing modules but will prevent new functionality from working.
• New hook_domain_warnings_alter() for cases where hook_domainwarnings() is possibly overridden by Domain Settings - http://drupal.org/node/721148
• Now with basic Drush support
• Generate domains on the fly with Devel

• admin's blog
• 
• print
• email