Google is now using images captured using both kites and balloons by individual users. The images started turning up in Google Earth last week, and Google says the resolution captured using the sources is impressive. Google notes that The Public Laboratory for Open Technology and Science has been hard at work making this sort of data collection easy and cheap.
The Public Laboratory has developed an open-source balloon mapping toolkit that works with a cheap digital point-and-shoot camera. That balloon mapping toolkit costs about $100 including the balloon, helium, line, soda bottle, and other parts needed in the build. The laboratory also offers a special web-based tool called MapKnitter that allows the user to align the photos into geo-referenced images.
Once those photos are aligned, the data can be used by Google Earth and other digital mapping tools. Google notes that many of the images that the Public Laboratory had in its archive have now been ported into Google Earth's historical imagery database. This sounds like an interesting way to get better coverage of your home or neighborhood.