How do I use UTC with NTP?
OSX has NTP built in, and enabled by default already.

From the Apple menu -> System Preferences -> Date and Time

Make sure that Set Date and Time Automatically is checked. That's NTP. You can pick a default Apple NTP server, or set your own, eg. pick one from here: http://www.pool.ntp.org/zone/north-america

For UTC time zone, click over to the Time Zone tab, and enter "UTC - United Kingdom" as the Closest City.