Here is a neat little Google Earth file that has often been helpful on many of my field trips when trying to remember where time zones start and stop. Just open the file in Google Earth, then point and click your location to get info on that time zone.
The file overlays a custom polygon time zone map, then allows the user to click anywhere in the world to produce a pop up bubble containing a running clock with the time zone (GMT) and the current time for that area, although does not seem to make the daylight savings adjustment.
Every now and then I come across some little utilities that help to make things easier while working in the field and these pages are mainly my way of sharing them with others while creating a go-to place where I can easily find them when I need them. If you know of any other mapping related utilities like this then let me know and I may include it here on my site with the others.