VMware ESX and ESXi 4.1 Comparison

VMware ESX and ESXi 4.1 Comparison

http://www.vmware.com/products/vsphere/esxi-and-esx/index.html

http://www.vmware.com/products/vsphere/esxi-and-esx/compare.html#c177109

Upgrade from ESX to ESXi

http://www.vmware.com/products/vsphere/esxi-and-esx/upgrade.html#c177045