8/13/2009: No longer free; there’s a subscription fee from which a small charge is deducted for every use. A free grid link is still available here for MGRS and UTM.
Earthpoint has a new beta Google Earth function – grid overlays for multiple coordinate systems:
- Deg – Decimal degrees
- DegSec – Degrees, Decimal seconds
- DegSecMin – Degrees, Seconds, Decimal minutes
- Georef – World Geographic Reference System
- UTM/UPS – Universal Transverse Mercator / Universal Polar Stereographic
- MGRS – Military Grid Reference System
Click the button for the desired grid KML file, and open it in Google Earth (UTM here):

As you zoom in, the grids become finer; you may have to wait a bit for the network link to catch up:

Roll your mouse over one of the “balls” defining the grid, and get a pop-up with the coordinates (and UTM zone here):

The crosshair marks the center of the display, the location for which Google Earth shows the coordinates and elevation in the bottom toolbar.
Related posts:
- MGRS/UTM/Latitude-Longitude Converter
- Degree-Minute-Second To Decimal Degree Converter
- Spreadsheet Tools For Lat/Long, MGRS and UTM Coordinate Conversions
- Useful "Nearby" Utilities For Google Earth
- Options For MGRS Coordinate Conversion And Viewing
- Coordinate, Elevation, Distance And More In Google Maps
- Google Earth Coordinates In Multiple Projections With Plex.Mark
- Yet Another Way To Get Position Coordinates In Google Earth
- Online Lat/Long – UTM – Grid Coordinate Converter
- Drawing Grids, Paths And Polygons In Google Earth Using GE-Path

You have many nice posts and useful tools.
I would also like to suggest you a free tool you might find useful because it creates placemarks and reads coordinates from Google Earth for 2.000 coordinate systems around the world.
It’s named Plex.Mark!:
http://www.plexscape.com
Best regards and keep up the good work!
These overlays are not free: “If you are not using an account, then you are limited to five moves in Google Earth.
Annual, Quarterly, Monthly subscriptions – unrestricted use.
“Pay For Use” subscription – first five moves are free. After that, $0.01 is deducted from your pre-paid account for each move in Google Earth.”