vSphere 4.0 Best Practices
VMware has released a series of KB articles outlining the requirements and best practices for installing vSphere, upgrading to vSphere, and upgrading ESX 3.0 virtual machines to ESX 4.0 hardware. VMware also provides a vCenter Installation Worksheet that could be useful for documentation purposes. Links to these KB articles are provided in this post along with quick quotes and notes providing additional information on each topic. Be sure to read the KB articles for the best practice details.
Further details over here