This is slightly off topic, because it has to do with the difference in openness between Europe and the USA. In America, if you want to use Google's or Yahoo!'s maps in your own application, it's easy. You use a zip code to pick up geographic coordinates from a number of free sources (even Yahoo! itself) and away you go.
In the UK (and I think in many other countries) where our taxes have paid for the creation and collection of postcode and geographic data, we're obliged to pay again. The powers-that-be do not understand that this is crippling the potential for hundreds of useful map-related services. Many of them provided for nothing by enthusiasts.
There is a campaign afoot to change this. Please read a more articulate explanation from Paul Miller (I'm in a hotel room on the edge of the Eastern Mediterranean at the moment and have a cab coming in a few minutes) and connect to the petition if you support it.