You can do the usual screen-grabs to get an image. A nice free program for this is MWSnap.
Otherwise (after a quick look at the web-site):
It looks like the map images are geo-referenced, tiled (split into bits) and stored at different resolutions on the beatentrack server. The relevant tiles are then served up using the Google Maps interface as you pan and zoom. You could reverse-engineer the javascript to get the tile names and then retrieve each tile... but that looks a bit painful, maybe better off emailing Juffy and asking him if the original map files are stored anywhere accessible before tiling..... and of course I may have read that javascript all wrong, its not something I'm very good at.
