Happily, RaceReplay.net works fine -- although it uses the 'CTP' of Microsoft's Map control - the RTW requires SL3 which might throw a spanner in the works :-(
The DeepEarth open-source DeepZoom-based map control does work, however, which is great.
Searcharoo's Silverlight UI breaks with
Could not load type 'BufferedStreamReader' from assembly System.Json so I'll have to investigate that; might have to get a different Json lib.
Anyway, IMO Moonlight 2.0 is a great achievement by Novell and the VPC is a great way for .NET developers to learn about it... have fun!