I am 19 weeks pregnant. Does listning to classical music really help my unborn child by making it a tad smarter? If so, can he hear it if its softly played next to me or would headphones on my belly work better?

It is believed that this helps, but is more of an old wive's tale than anything. Smarts are genetic, they come from genes passed all the way back in your history.

It is soothing though. But at 19 weeks I am not really sure if the baby can hear much. Using the headphones on the belly is better cause the sound passed from the room through the amniotic fluid would be distorted.

Try this... Take a bath with the radio in the bathroom... put your hands over your ears... put your head under the water... listen to the music. This is similar to what the baby would hear.

There is some evidence for this. It has been collected in a book called 'The Mozart Effect' and summarized in some articles by the same name. However, J_9 is correct in pointing out that there is relatively little the baby can actually hear. Some of the effects may be coincidental/environmental; for example, certainly children who enjoy peace and security are markedly better learners, and an environment that is caring for the child to this degree provides other positive influences as well.