This is a set of icons based on the work of Gerd Arntz: http://www.gerdarntz.org/home 

Prepared by Chris Blow and Caleb Bell.They are freely reusable in noncommercial contexts. These were first used in the 2010 deployment in Haiti at http://haiti.ushahidi.com.

Overview with example treatments on various backgrounds: 

http://github.com/unthinkingly/ushahidi-haiti-icons/blob/master/overview.png

See also: http://developmentseed.org/blog/2010/feb/04/maki-mapping-icons-available-under-bsd-license
And: http://athleticsnyc.com/print/unitednations-ocha-symbol-set
And: thenounproject.com/

This is part of a larger ongoing project for pictographic humanitarian map design; others may be released at some point. If you have questions or ideas about the direction of the icons please contact cgblow@gmail.com.

Roadmap: We are currently looking into ways to automate the customization of the icons, to create a larger set for use in humanitarian mapping contexts. Let me know if you would like to collaborate!