I thought it would be a good idea to start a free software thread.
Here are few I know of:
GIMP, to edit images (http://www.gimp.org/)
IrfanView, to view images (http://www.irfanview.com/)
XnView, to organize images (http://www.xnview.com/)
PhotoME, to edit Exif properties (http://www.photome.de/)
BatchPurifier LITE, to delete metadata from jpeg (http://www.digitalconfidence.com/downloads.html)