At Tech Ed 2007 in Orlando, I had a chance to interview a group of folks with the Exchange Team. One of these interviews was with Becky Benfield, Principal Program Manager. She was kind enough to be interviewed again (I interviewed Becky during Tech Ed 2006 in Boston as well). In this interview, she gives us a quick explanation of some enhancements with High Availability in Exchange Server 2007 SP1 - especially around Standby Continuous Replication (SCR). To view the video interview, go here: http://msexchangeteam.com/videos/9/drandha/entry446453.aspx.
Harold Wong's Blog showcases a couple of Exchange Server Team interviews he recorded while at TechEd
This is some great stuff around the new SCR featureset. Unfortunately there still seems to be less-than-thorough coverage of the SCR implementation availible in the public at this point.
You are correct. I would ask that you be patient at this time as SP1 is still in beta. There will be detailed documentation when we get closer to release of SP1 or shortly after. Thanks.