RasMol is a molecular viewing program that can be used to visualise .xyz files. You can use it, for example, to look at snapshots from your simulation and or potential map (after using mapdisplay). Full documentation can be found HERE
Some basics:
Open a xyz file:
rasmol -xyz [filename.xyz]
If you put a & after you cannot enter commands to RasMol and can only move it around with your mouse.
spacefill [number]
This will give you different sizes of spacefill when in spacefill view
select [atom name]
This will select the named atom and allow you to resize them with the above command or use:
colour [colour]
To change the colour of the selected atoms
To capture a picture of the screen either press the "Print Scrn" button then paste into paint or
goto export, postscript then type a filename into the shell window with the ending .ps