Projection
Projections and Datum Transformations
PRJ files (in the usual WKT format) as used by recent versions of ESRI ArcView http://esri-germany.de/downloads/software/Koordinatensysteme.zip
http://support.esri-germany.de/files/support/KoordinatensystemeInDeutschland.pdf http://support.esri-germany.de/files/support/KoordinatensystemeNachbarnDeutschlands.pdf http://support.esri-germany.de/files/support/KoordinatensystemeWeltweit.pdf
http://www.epsg.org/Geodetic.html
http://www.alectoria.at/content/view/17/1/
Google Map Projection
http://www.sharpgis.net/2007/07/27/TheMicrosoftLiveMapsAndGoogleMapsProjection.aspx http://cfis.savagexi.com/articles/2006/05/03/google-maps-deconstructed