Silverlight 2.0 Beta 2 is out earlier than originally announced. You'll also find a new Deep Zoom Composer available shortly (link may be broken for some as it propagates across the innertubes. Brandon has a good writeup here including download links:
The Windows Experience Blog : Silverlight 2.0 Beta 2 and Deep Zoom Composer Update
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.