Hightlights of this CTP:

• ADO.NET 3.0 Advancements
• LINQ over XML (XLinq)
• Multi-targeting
• Improved 64bit application working set
• Lightweight reader/writer lock with deadlock-free upgrade support.
• A high performance trace listener which logs XML to disk in the event schema.
• Getting VSTO and/or controls off machine policy/legacy policy migration
• Security Platform Parity - Suite B support: AES
• A new date time data structure that can specify an exact point in time relative to the UTC time zone.
• New IO types that expose almost all pipe functionality provided by Windows.
• A new high performance set collection.

Many congrats to the team. You can download it from MSDN: http://www.microsoft.com/downloads/details.aspx?FamilyId=C09B5A2D-EB6A-44B6-8BBD-3764A2FDA9CE&displaylang=en

Enjoy!