The February CTP build of the WinFX SDK and also the Orcas February CTP will both feature Crossbow.

Crossbow will allow you to use WPF functionality on existing Windows Forms.

Read more on: http://blogs.msdn.com/mhendersblog/archive/2006/02/01/522723.aspx

Update:

There is also an MSDN show on MSDNtv: http://msdn.microsoft.com/msdntv/episode.aspx?xml=episodes/en/20060216CrossbowMH/manifest.xml