Heidelberg is the first city I’ve seen that has started to offer local Wifi coverage in combination with a mobile optimized city portal for tourists. Supported mobile devices are Windows Mobile, Palm, the Nokia 770 Internet tablet and Safari / Nokia S60 phones. In addition to pictures and textual information the web site offers localization and audio guides:
The Heidelberg-mobile site can be accessed from anywhere via the Internet or a wireless 2G or 3G network or via one of the hotspots in town. If accessed via the local Wifi hotspots (hello people with N-Series Wifi enable Nokia phones!) your position is analyzed by the web server and maps of the city will be centered around your current location. Very helpful if you don’t know your way around.
I like audio guides in museums. Heidelberg-mobile goes a step beyond and offers audio guides for sights all around the city. Once you are at one of the attractions covered by the audio guide you can listen to it on your phone. The audio data is transfered over the Wifi network or in case you "only" have a 2G or 3G phone via an IP connection over UMTS or GPRS. This is a great idea, so I gave it a try on my N93 via my Wifi network at home. The audio files can be played by following the link to the audio guide section on the web site and selecting one of the links which lead to a specific story (sorry, all in German for the moment). After a few seconds the files are downloaded and are then played back in the media player.