GM related

Chevrolet - www.chevrolet.com
Cadillac - www.cadillac.com
Buick - www.buick.com
Pontiac - www.pontiac.com
GMC - www.gmc.com
Onstar - www.onstar.com
XM Radio - www.xmradio.com
GM 100,000-mile Warranty - www.gm.com/warranty/index.jsp?brandid=vs&lang=en&cmp=gm_com
GM Live Green, Go Yellow Flex-Fuel Center - www.livegreengoyellow.com
GM Navigation System and Disc Center - www.gmnavdisc.com
GM Owner Center - www.mygmlink.com
GM Corperation - www.gm.com
GM Fleet and Commercial Ops - www.gmfleet.com
GM Mobility Assistance - http://www.gm.com/automotive/vehicle_shopping/gm_mobility/
GM Goodwrench Service - www.gmgoodwrench.com
GM Parts and Accessories Zone - www.gmgoodwrench.com/accessoriesjsp/home.jsp
NASCAR GM Goodwrench Racing - www.gmgoodwrench.com/Racing/index.jsp

Other

Carfax - www.carfax.com
Kelly Blue Book - www.kbb.com
U.S. Fuel Economy Infomation - www.fueleconomy.gov
Consumer Reports - www.consumerreports.org
JD Power Ratings - www.jdpower.com