This is absolutely fantastic news! A news release on Microsoft PressPass announces that Longhorn will be available in 2006 and get this Avalon and WinFX will be made available to Windows XP and Windows 2003 in 2006 along with the release on Longhorn. So what does this mean? Apps you write to make use of WinFX, WinFS and Avalon can run on all your client machines, man this is freaking exciting.

At a meeting today with several hundred of the company’s top developer evangelists from around the world, Microsoft also announced that the Windows WinFX developer technologies, including the new presentation subsystem code-named "Avalon" and the new communication subsystem code-named Indigo, will be made available for Microsoft® Windows XP and Windows Server 2003 in 2006. This availability will expand the scope of opportunity for developers by enabling them to write applications that can run on hundreds of millions of PCs, resulting in enhanced experiences for users of those operating systems.

Read it here.