http://www2.census.gov/cgi-bin/shapefiles2009/national-files --> http://www2.census.gov/geo/tiger/TIGER2009/tl_2009_us_aiannh.zip
http://epa.gov/nheerl/arm/documents/design_doc/estuary_design.zip
http://pubs.usgs.gov/sim/2991/downloads/SIM2991.zip
http://pubs.usgs.gov/sim/3120/downloads/datafiles/ --> PROJCS["NAD_1927_UTM_Zone_15N",GEOGCS["GCS_North_American_1927",DATUM["D_North_American_1927",SPHEROID["Clarke_1866",6378206.4,294.9786982]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-93.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]
/vsicurl/http://pubs.usgs.gov/sim/3120/downloads/SIM3120_sheet1_GeoPDF_v1-1.pdf --> PROJCS["WGS_1984_UTM_Zone_42N",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",69],PARAMETER["scale_factor",0.9996],UNIT["Meter",1]]
http://pubs.usgs.gov/sim/3120/downloads/datafiles/kabul_north_landsat_731.prj --> (weird : contains AUTHORITY node) PROJCS["WGS84_/_UTM_zone_42N_(CM_69E)",GEOGCS["WGS84_/_Geographic",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.2572235630,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0.0],UNIT["Decimal_Degree",0.01745329251994330]],PROJECTION["Transverse_Mercator"],PARAMETER["Latitude_Of_Center",0.0],PARAMETER["Longitude_Of_Origin",69.0],PARAMETER["Scale_Factor",0.9996000000],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG","32642"]]
http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Ag_Atlas_Maps/mapfiles/CoGenAll_GCS07.zip
/vsizip//vsicurl/http://downloads.cloudmade.com/oceania/australia_and_new_zealand/new_zealand/new_zealand.shapefiles.zip/new_zealand_poi.prj --> GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]
http://data.nodc.noaa.gov/DeepwaterHorizon/Fisheries_Monitoring/Fisheries_Closure/20100502/EmerRule_050210_po.prj --> PROJCS["North_America_Albers_Equal_Area_Conic",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Albers"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-88.0],PARAMETER["Standard_Parallel_1",28.5],PARAMETER["Standard_Parallel_2",30.0],PARAMETER["Latitude_Of_Origin",28.0],UNIT["Meter",1.0]]
http://opendata.paris.fr/opendata/hn/VOL_NBATI.zip --> PROJCS["Lambert I Nord",GEOGCS["NTF",DATUM["D_Clarke_1880_IGN",SPHEROID["Clarke_1880_IGN",6378249.2,293.46602]],PRIMEM["Paris",2.337229166666667],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",600000.0],PARAMETER["False_Northing",200000.0],PARAMETER["Central_Meridian",2.337229166666667],PARAMETER["Standard_Parallel_1",48.59852277777778],PARAMETER["Standard_Parallel_2",50.39591166666667],PARAMETER["Latitude_Of_Origin",49.5],UNIT["Meter",1.0]]
http://fpk.unair.ac.id/webo/Tjnung%20Emas%20Hasil%20Kroscek/Part%201/052444615020_01/GIS_FILES/052444615020_01_ORDER_SHAPE.prj --> GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
http://www.hydroquebec.com/soumissionnez/documents_consultation/doc_13881340.html
http://www.hydroquebec.com/soumissionnez/documents_consultation/13881340/Addenda_1/chemin_13881340_polyline.prj --> GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
http://developer.metro.net/introduction/gis-data/download-gis-data/ -->                                             GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
http://hawaii.gov/dbedt/gis/Assisted_Living.htm ->                                    PROJCS["NAD_1983_UTM_Zone_4N",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-159.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]
http://pireh-dev.univ-paris1.fr/wikiCarto/lib/exe/fetch.php?media=1848region.prj --> PROJCS["Lambert_Conformal_Conic",GEOGCS["unnamed ellipse",DATUM["D_unknown",SPHEROID["Unknown",6378249.2,293.4660200000038]],PRIMEM["Unknown",2.337229166666667],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["standard_parallel_1",48.59852277777778],PARAMETER["standard_parallel_2",50.39591166666667],PARAMETER["latitude_of_origin",49.5],PARAMETER["central_meridian",2.337229166666667],PARAMETER["false_easting",600000],PARAMETER["false_northing",200000],UNIT["Meter",1]]

A must :
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp/gcs.htm
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp/pcs.htm