Your Blood Alcohol Concentration
Wikipedia has an entry with a thorough description of many medical and legal issues regarding blood alcohol content.
This calculator determines its results by calculating the factors of ounces consumed, weight, and the amount of time passed since the first drink.
This preliminary BAC calculator can give an estimate of your blood alcohol concentration. Be aware that it is not entirely reliable, as it does not factor in many important variables; it does, however, consider gender and weight.
The developers of the Intoximeter Breath Machine hold a discussion both on alcohol and blood alcohol analysis.