Aetna Intelihealth
Aetna: Inteli Health: Using a Peak Flow Meter
This article briefly describes how a peak flow meter can help you determine the severity of your asthma using peak flow "zones."
Mayo Clinic
Mayo Clinic: Asthma
This is a great starting point for anyone doing research or a report on asthma. Organized into several sections -- including "Signs and Symptoms," "Screening and Diagnosis," and "Treatment."