VMware has created a standalone processor check utility which you can use without VMware Workstation to determine whether your CPU is supported for virtual machines with 64-bit guest operating systems.
This utility is a handy way to check a system before you buy it. Download it onto a USB key and run it on the prospective computer to see if it will run 64 bit guests.
It's important to note that you do NOT have to run a 64 bit host OS to run 64 bit guests in VMware 6. For me, this is really handy since none of my wireless USB Ethernet adapters have 64 bit drivers. I can use x86 XP as my host OS to access my wireless network while still running 64 bit guests like Windows Server 2008. Sweet!