The June CTP of the .NET Framework 3.0 is available. This version contains a number of significant updates for WCF that you will see highlighted here and on the team member's blogs in the upcoming days and weeks.
Please note that there is no Go-Live license available for the June CTP. Also mind that the standalone installer is not compatible with Windows Vista Beta 2, because the .NET Framework 3.0 is integrated into Windows Vista. For members for the Windows Vista Beta program, post-Beta2 builds of Vista including newer versions of the .NET Framework 3.0 similar to this CTP are available through Microsoft Connect.
Download the June CTP for Windows XP SP2 and Windows Server 2003 here.