There is no supported function for doing this. Attached is a modified version of GINPUT, which references a third party function cursorLocation.m, found at: http://iheartmatlab.blogspot.com
This modified GINPUT will display the X and Y values at the current cursor location in the top left corner of the figure. Note that this modified function has only been tested with figures that have a single 2D axes and will produce an error if used with a blank figure.