Terry on the Microsoft Exchange Team Blog announced the release of Exchange 2007.
We've bet the company on this product. Here at Microsoft, we have over 120,000 mailboxes running in production on Exchange 2007 – exceeding our SLA of 99.95% availability. Likewise, over 200 Technology Adoption Partners and Rapid Deployment Partners have over 55,000 mailboxes in production operating within their enterprise SLA’s.
In addition to taking the time to ensure this software was rock solid for you, we've invested more time in documentation and deployment guidance than we have for any other release previously. Please do check it out and let us know if we're missing something you need.