Microsoft Online Services Service Update for Oct 2009 is currently being deployed into production data centers and is scheduled to be available to all customers before the end of October. The following features and capabilities’re included in this Service Update:
Bulk Activation of Users enabling administrators to easily automate the activation of a set of users.
Supported e-mail clients for Exchange Online are being expanded to include POP-based clients.
Microsoft Online Services Administration Center will support as many as 30,000 users
Enhanced Support for Mac OS includes several enhancements that’ll provide a more efficient communication and collaboration
Full Article: MOS blog