Create simple map implementation

I need help with creating a display of purchases using a stylized map of Sweden (white silhouette on black background, see attached vector art). I already have a script which returns new purchases and their city/zip code, all I want is for a dot to appear on the map where the purchase was made. This can be done using one of many methods, probably the first one coming to mind being Google Maps. My current PHP application is returning a json looking something like this: [{"name":"something","org":"something,"from":"2013-02-08 15:11:06","id":"2080987","zip":"72136", "city":"Stockholm"},{"name":"something_else","org":"something_else","from":"2013-02-08 15:12:03","id":"2080988","zip":"27432", "city":"Malmö"}] The only things of interest to you are city and zip. Probably you'll want to use the city to map as it has better precision than zip code, and it should be easier as well. What I'm looking for here is a HTML/JS file calling my php application for the json every minute, and displaying new purchases on the map based on city, and/or zip.