On Youtube, I saw a Hak5 interview with a person who uses balloons to map events using a high altitude balloon - interview starts around 2 minutes. http://www.youtube.com/watch?v=_jyOu5TetKw&feature=g-u-u He mentions how to use balloons to map, and what the restrictions are.

Referenced links in the article http://publiclaboratory.org/map/toorcamp-2012-makah-passage-neah-bay-washington/2012-08-09

http://mapknitter.org/