Disney has included coin press locations on its website (disneyworld.com/coinpresses), which is also advertised on the machines. The list is terrible. It puts Epcot pavilions in the wrong location, and appears to be missing some machines (I will check next week to see if the two machines at the Outpost shop outside Animal Kingdom are really gone).
The vendor who operates the machines, CTM Group, has more reliable maps on their website (http://www.ctmgroupinc.com/disney/), which is also offered as a phone app. Even they miss a few, though.
Guest services keeps maps and lists, too, but these have never been reliable. The best source remains Presscoins.com.