Google Maps and public transit

This and this are both really cool examples of folks hacking google maps and firefox to do some really neat stuff.
Some very bright folks have taken the maps from the Chicago and Boston public transit systems and made them available via Google Maps so that you can look up an address and find it on a map that shows the nearest bus or train stop.
Now, if we can just get the folks at Google Maps to include public transit information by default as a transparent overlay of their existing maps that would be even cooler.