Last year my friends and I all bought sea-bands. They are elastic wrist bands that have a "button" on the inside. WHen you put them on properly, the button pushes against a pressure point in your wrist that helps to alleviate motion sickness. You can wait until you feel sick to use them, and there is no medication involved! According to the box, they are also good for morning sickess associated with pregnancy. They worked well for us last year!
Also heard that ginger tablets work well, although I've never tried them.
Congrats on the baby! Have fun on the trip!