A great new feature was added to Google Apps–Google’s business fleet of web-based office software. Google Apps now supports multiple domains.
Prior to this update, if you owned multiple web domains, you would need to have several Google Apps accounts–one for each. As part of the upgrade, there is a new admin control which gives a single panel hotbox for managing the different domains.
Sharing is also expanded with this upgrade. You will now be able to share documents across domains.

