VMware has provided a utility called VMware Site Survey that will run a compatability check against your environment and produce a report that will let you know what, if any, issues you need to fix before turning on Fault Tolerance for VMs.
VMwares CPU ID Utility is also a great tool for displaying compatability with various other advanced CPU features in your environment.
For a detailed list of what is required to run VMware FT, please see: VMware Fault Tolerance KBÂ Article
