I originally ran into this post http://www.stefanschuller.com/guides/guide-keeping-time-in-esx.html which looked like a lot of work to get NTP up and running. Well I’m glad to say that with version 3.5 you can set the time in the virtual center GUI 🙂 just click on your ESX host, go to the configuration tab, then time configuration and you can set your ntp servers. Then you can set your VM’s to use the VM time synching and disable the windows time service.