http://www.openstreetmap.org
http://leafletjs.com/examples/geojson.html
http://leafletjs.com/plugins.html

http://www.maptools.org
http://openlayers.org
http://openlayers.org/dev/examples/
http://www.openstreetmap.org

http://cloudmade.com
http://geojson.org

PRICED:
https://www.espatial.com/
http://www.esri.com/
http://mapnik.org
http://mapbox.com/

http://www.arcgis.com
http://www.arcgis.com/home/webmap/viewer.html?webmap=fe44cf9a739848939988addfeba473e4&center=-112.514677,36.294582&level=10
http://www.arcgis.com/home/webmap/viewer.html?webmap=8b3d38c0819547faa83f7b7aca80bd76

http://gis.thinkgeo.com/Products

INFO:
http://www.pbs.org/idealab/2010/10/mapnik-the-coolest-mapping-software-youve-never-heard-of301.html

http://visitmix.com/labs/ai2canvas/channel9.html