Myth #1: Lifting weights makes you look like the Hulk, minus the green skin and unfortunate cutoff purple shorts. BUSTED! Unless you do steroids (a la ARod and Barry "my head was always 36 inches around" Bonds) you will not bulk up. Lifting weights makes your muscles stronger but you have to take supplements and do very specific workouts to add bulk.
Myth #2: Cardio is the best way to lose weight. BUSTED! While cardio is an essential part of a well rounded workout plan, combining cardio and weights is the best way to lose weight. Lifting weights increases your muscle mass and muscles burn more calories at rest than fat. Thus, (I love this part!) if you have more muscle mass you burn more calories just hanging out watching TV:)
Myth #3: Lifting weights doesn't burn that many calories. I'm not getting that much out of my gym time if I just lift weights. BUSTED! Lifting weights has the great benefit of a high after burn. After burn is the calories you burn after you are done working out. If you lift weights for an hour, you will burn an extra 100 calories or so over the next 24 hours. That means three weightlifting sessions in a week equals 300 extra calories which is about what you would burn running three miles!