ShowCell adds a spell - ShowPlayerLocation, that when cast opens a messagebox with the current cell's form ID and the players coordinates. This is to allow modders to find places in game that they would like to use in their mods and easily find them in the creation kit. 

requirements - none.
Install - extract to data file, or use a mod manager.

Don't have the spell?
If for some reason you don't have the spell, I placed a spell tome on the water well in the market of Whiterun.

How to find the cell in the creation kit?
In the creation kit, find the 'edit' menu on the toolbar at the top left of the screen. On the context menu, find 'Find Text'. In the 'search text' box, enter the form id that wrote down while in game - hit enter. Below the search box are a number of tabs - 'infos', 'scripts', 'objects etc'. Click on 'objects etc'.

Another way is, if the cell is an exterior cell, click the world space drop-down menu in the cell window of the creation kit and choose Tamriel. Just below the drop down is a box for the X and Y coordinate of the wilderness you want to load. Just input the coordinates from in game and click go and it will load the cell. This only works for exterior cells!

And wallah! The cell will be in the list, double click it to load the cell.

Something else to note - 
Although this mod doesn't expose coc codes, you can use the centre on world - cow - command to teleport to exterior cells. so for example, in the console window : cow Tamriel 10 -4.