The best interactive map of bangkok can be found at Bangkok Bob's website:  http://www.bangkokbob.net/city_map.htm

This is a good interactive map for finding special places ... shopping, museums, tourist sites etc etc:  http://www.into-asia.com/bangkok/maps/

This map is very interactive and zooms in to incredible detail.  Sometimes a bit too incredible!:  http://www.hot-maps.de/asia/thailand/bangkok/homeen.html