Or is it?!

Vmware ESXi allows you to run all your production applications at near-native performance on VMware’s next-generation OS-independent hypervisor, now available for free. It has the same functionality and performance as VMware ESX but with a 32 MB disk footprint. With the ability to seamlessly upgrade to VMware Infrastructure 3, customers can add the benefits of server consolidation, automatic load balancing and business continuity to VMware ESXi.

On paper, ESX 3i is free to compete in the press with Hyper-V. Microsoft’s Hyper-V is free, however if you want to manage Hyper-v by SCVMM you’ll have to pay in the order of US$3,000 which is similar to Vmware ie. if you want 3i to be managed by virtual center.

They’re evil geniuses! ESX 3i is now free, but it can only be managed with Virtual Center. So you have to buy at least a Foundation or Standard licence anyway!!!

Thanks to Jason (http://geeklog.lucid.net.au) for the following additional info outlining the differences between the stand alone hypervisor (3i) and the managed version (with Virtual Center)