Seems like everytime I run a course on Asp.Net Ajax, Microsoft release an update in the middle of it!
Last time was very tricky - there were some big differences from the CTP's to BETA 2.
I'm hoping the RC changes aren't so dramatic because I am covering it in my course tomorrow. Could be a late night...
http://ajax.asp.net/default.aspx?tabid=47&subtabid=471
Cheers
Ian