Exchange Server 2010 beta was released to the public this week. The beta for EWS managed client API has also been released.
Check it out the related blog posts:
Presenting Exchange Server 2010
Introducing the EWS Managed API
This is especially exciting for me because I am currently working as the beta support engineer for developer support. What that means is that I am support customers who are working with Exchange Server 2010. I hope to post some content here about what's available to developers in Exchange Server 2010.