Live Communications Server 2005 Capacity Planning Toolkit
Today Microsoft release a planning toolkit that will help in understanding the needs prior to implementation.
It covers
Hardware planning
Best practices for performance tuning
Ability to verify the performance of your deployments
http://www.microsoft.com/downloads/details.aspx?familyid=107a5e83-ca59-4bcb-a3bc-27efd97a477d&displaylang=en