Google Maps has an experimental feature for downloading map information. I don't think it currently includes transit yet but I'm sure it will in the future.

http://googlemobile.blogspot.com/2011/07/download-map-area-a...

For cities that provide the information to Google, Maps includes realtime delays and closures.

http://googlemobile.blogspot.com/2011/06/know-when-your-bus-...