Automobile Purchasing
Automobile Fuel Economy - Find gas mileage ratings for new cars

Autotropolis.com - Automotive Research site with in-depth new and used vehicle reviews, photos, as well as user forums, blogs, a wiki based engine, etc.

Carfax.com - Find out if the used car you're considering has been in a major accident, has false milage or some other problem.

DealerNet - Information on new and used cars

Edmunds Automobile Buyer's Guides - New and used car and truck prices and reviews

Kelley Blue Book - Used car blue book values and new car pricing

NADA Appraisal Guides - Blue book values for used cars and other vehicles

General Automotive Information
AAA Foundation for Traffic Safety - Information on traffic safety.

CARS - Vehicle and Equipment Information. National Highway Traffic Safety Administration information on safety, testing, etc.