Xtravirt does it again.  This paper describes what you need to install ESX 4.0 on Workstation 6.5.2.

Being able to run VMware ESX 4.0 under VMware Workstation as a VM gives users and professionals in the IT community great flexibility when it comes to learning, experimenting or even demonstrating the product. Needless to say, this is not an officially supported deployment.

The approach is fundamentally no different to that previously devised for VMware ESX 3.5, the main difference simply being the change in minimum hardware requirements.

This Xtravirt white paper provides this information along with the installation instructions for this environment.

Key Concepts:

• Step by step install guide for VMware ESX 4.0 as a virtual machine within VMware Workstation 6.5.2

Download "How to Install ESX 4.0 on Workstation 6.5.2" here, login required.