March 2005 Indigo CTP is now available to download for MSDN Subscribers at http://msdn.microsoft.com/subscriptions/default.aspx
This should also be available to the broad public soon.
For more information, go to the Longhorn developer center ( http://msdn.microsoft.com/longhorn/ ) and the Indigo page ( http://msdn.microsoft.com/Longhorn/understanding/pillars/Indigo/default.aspx ), which will be updated with new information throughout the week.
I encourage everyone to send me the feedback you might have on the transactions features available in this CTP. You can post a comment to this post, or if you prefer, use http://blogs.msdn.com/florinlazar/contact.aspx to send me a private message. Thanks!