Offline Maps is one the application at Codeoplex which needs a lot of appreciation, specially by Map Lovers. This application lets you download maps from Google or Open Street Maps and then lets you mark, zoom, rip, draw paths and even tiles i.e. particular section of the map only. Also included is the GPS support which lets you find position, draw a trace route which is useful for travelers and then display it.
If this software can be taken to commercial level can turn to be a boon for developing custom travel maps etc by the travel industry.