MSDN Video covering the removal from MSMQ 5.0 of the Windows 2000 client support service
And 3rd in the trio created for Windows 7 / Windows 2008 R2, we have:
Microsoft Message Queuing (MSMQ) - Removal of Windows 2000 Client Support Service
where Nancy Strickland discusses the impact of installing Windows 2008 R2 domain controllers on Windows 2000 machines running MSMQ applications.