http://kb.vmware.com/kb/2004501 - This video discusses and demonstrates upgrading a VMware ESX 4.x server to ESXi 5.0 using VMware vSphere Update Manager. Be sure to read the information provided in VMware Knowledge Base article 2004501 before attempting an upgrade to ESXi 5.0.
Additional documentation for the VMware vSphere 5 product is available at http://pubs.vmware.com/vsphere-50/ind... and https://www.vmware.com/support/pubs/v...