It's fun, isn't it? When I was pregnant with my son, I had morning sickness almost every day, all day, for 5 months. At it's worst, I couldn't even keep down water.
I've found that one thing that really helps is to eat what you're craving (provided it's actually food, and not something that will harm the baby). Often during pregnancy, when you're craving something specific, it's because it's something your body needs - like a certain vitamin, for example - and it might work harder to keep it down.
Something else that helped was to drink a lot of liquids. This doesn't make the nausea go away, per se, but if you do have to throw up, it will be a hell of a lot easier with more liquid in your system! :P
If it gets so horrible that you can't keep down water, like me, then there are prescription drugs that will help. Doctors don't like to mention them because they can be expensive and they'd rather you go without drugs - but at the same time, if you can hold down any food that's not good for you either! If worst comes to worst, ask your doctor. I went on Diclectin (I think) when it got to it's worst. I took it for about a week or so, and then my body started throwing THAT up, so I went off it and felt fine from then on out!