Brian (Kronberg),
>>Windows 2008 server will allow for a single AD site to span multiple
>>subnets which will finally allow you to have a single CCR setup in two
>>routed networks.
What you're referring to is the limitation of Windows Server 2003 clusters to have all nodes on the same IP subnet, which requires stretching subnets to a remote location.
Windows Server 2008 allows cluster nodes to be in different IP subnets, making stretching the subnet unnecessary. However, Exchange Server 2007 (RTM and SP1) requires that all nodes in a cluster be in the same AD Site. 2 cluster nodes can't be in different Sites - both subnets need to be associated with the same AD Site.
Bharat