General pulmonary hypertension sites:
Pulmonary Hypertension Association
American Heart Association patient page on PH
American Heart Association patient page on primary PH
PHCentral
PH Neighborhood
American Lung Association (fact sheet)
Scleroderma Foundation
NHLBI Pulmonary patient page on PAH
Echocardiogram sites:
HeartSite.com on echocardiography
MayoClinic.com on echocardiography
Heart Rhythm Society on echocardiogram