There is a lot of great information about dogs and dog training available on-line.  Here is a sampling of the information I've found exceptionally useful:

Here are a few articles from studies that show that dog training style, primarily those using dominance or fear-based motivators, increase aggressive responses in dogs.

Using 'Dominance' To Explain Dog Behavior Is Old Hat

A new study shows how the behaviour of dogs has been misunderstood for generations: in fact using misplaced ideas about dog behaviour and training is likely to cause rather than cure unwanted behaviour.  The findings challenge many of the dominance related interpretations of behaviour and training techniques suggested by current TV dog trainers.

If You're Aggressive, Your Dog Will Be Too, Says Veterinary Study

Describes a year-long University of Pennsylvania survey of dog owners who use confrontational or aversive methods to train aggressive pets, veterinary researchers have found that most of these animals will continue to be aggressive unless training techniques are modified.  The study, published in the February, 2009 issue of Applied Animal Behavior Science, also showed that using non-aversive or neutral training methods such as additional exercise or rewards elicited very few aggressive responses.

Dogs Are Aggressive If They Are Trained Badly

ScienceDaily (May 1, 2009) — Many dogs are put down or abandoned due to their violent nature, but contrary to popular belief, breed has little to do with a dog's aggressive behaviour compared to all the owner-dependant factors. This is shown in a new study from the University of Córdoba, which includes breeds that are considered aggressive by nature, such as the Rottweiler or the Pit Bull.

What Really Prompts The Dog's 'Guilty Look'

ScienceDaily (June 14, 2009) — What dog owner has not come home to a broken vase or other valuable items and a guilty-looking dog slouching around the house? By ingeniously setting up conditions where the owner was misinformed as to whether their dog had really committed an offense, Alexandra Horowitz, Assistant Professor from Barnard College in New York, uncovered the origins of the “guilty look” in dogs in the recently published “Canine Behaviour and Cognition” Special Issue of Elsevier’s Behavioural Processes.