i have the i-phone app, it's pretty cool but there is not a map, not even map by country with the site listed. so i've ordered the "De Agostini" world Atlas from Unesco website, it's wonderful, with all 2013 sites. Of course it's gonna be old in few years, given the trend of 25-30 new sites per year (which makes it impossible for any of us to see them all!)
few features of the i-phone app: the sites can be sorted by A-Z index, by year inscribed, by Country, by classification of site (Cultural, Natural, Mixed), by Region, by Favourites (you can your own favourites when you see them), by "Recently Viewed", by "Visited Sites" (of course you can make the count exactly like on this website). A very nice feature is the "Random" button, which displays a Unesco site at random.
Opening the site, there is a short description which can be expanded, a map showing where the site is located within the country, a photogallery (basic as in the Unesco website) and extra information.
Unfortunately no update for Google Earth yet :(