At the link below, you will find information about what has changed for the iSCSI Initiator, and MPIO in Windows 2008 R2.

Also, the first in the series of our new configuration and step-by-step guides is available at the same location, which covers the configuration and usage of the iSCSI Initiator for both R2 and Windows 7.

Bruce Langworthy
Senior Program Manager - Enterprise Storage Networking, iSCSI, FC, MPIO, Core Storage
Windows Core OS Division