The System Center Operations Manager 2007 Migration Guide has now released to the Web and is available from the documentation link here http://www.microsoft.com/downloads/details.aspx?FamilyID=d826b836-59e5-4628-939e-2b852ed79859&DisplayLang=en, or alternatively from the TechNet TechCenter documentation page here http://technet.microsoft.com/en-us/opsmgr/bb498235.aspx (waiting for publication to this page at the time of me blogging this :) )