I read somewhere that morning sickness is caused by low blood sugar, so just anything that gives you a bit of a boost really. I travel on the train every day which is pretty sicky, but always find some haribo sweets / ginger biscuits / chocolate buttons (anything you can pick at) really helps.
I've had a lot of really bad feelings and wanted to throw up many times, but really find that eating anything sugary stops it. I also find that if it's the mornings when I feel ill then I probably didn't have a big enough dinner the night before. Little and often is the way. I even have smarties and chocolate buttons by the bed so I can just melt a couple in my mouth as I can't sleep when I feel sick.
Apparently I read somewhere that anything that takes away saliva from your mouth is a good thing too, so things like hard boiled sweets and lollys.
Hope that helps! Eating really does help, I luckily haven't thrown up yet and the eating actually gets rid of the sicky feelings.
Michelle