J.F.
We've used MinuteClinic a few times. They won't treat babes under 18 months of age and only treat for simple, run of the mill illnesses. You pay the same copay you would normally. You sign in on a computer and will have to enter all your regular info the first time. Thereafter, it is faster. Each visit is about 15 minutes and you'll wait in line if there is one. Most close around lunch time for an hour.
Otherwise, we LOVE it when it is the most convenient source to a dr. (ped's office is closed or ped is out for the day and I don't trust the other one!).