From Tumblr user MrLinux comes a simple mod great for servers.

Coordinates Mod for Minecraft.
Coordinates Mod is simple. It takes the coordinates from the debug menu, rounds them to the nearest hundredth (or tenth if hundredth is 0), and displays them on the screen. Off by default, but can be turned on/off by pressing F4.
You may read more about it and installation here.
Coordinates Mod Download:
1.8.1 - Mediafire or adf.ly
1.9pre5 - Mediafire or adf.ly
1.0.0 - Mediafire or adf.ly
1.1.0 - Mediafire or adf.ly

via: Minecraft Scenery

From Tumblr user MrLinux comes a simple mod great for servers.

Coordinates Mod for Minecraft.

Coordinates Mod is simple. It takes the coordinates from the debug menu, rounds them to the nearest hundredth (or tenth if hundredth is 0), and displays them on the screen. Off by default, but can be turned on/off by pressing F4.

You may read more about it and installation here.

Coordinates Mod Download:

via: Minecraft Scenery