This is a great application from Martijn (his blog) – it’s a style editor for Mapnik – one of the renderers used to render Openstreetmap data.
It goes a long way to helping differentiate the map from the data, as I discussed in this post “a manifesto?“. OpenStreetMap’s power is the data. It also shows the flexibility of mapnik, and the Freedom in being able to have the map you want.
Have a go by selecting some of the predefined styles.
Chris has made a transparent openstreetmap layer, utilizing tilecache and mapnik configured for transparencies
with a neat overlay opacity control too.
example with landsat
example with yahoo images