We use iTALC monitoring software which is free. Our teachers seem to like it to manage their students computer activity.
Many schools have a system where the teacher can see what students are doing on their screen without having to walk around the room and monitor. This is set up on a teacher computer, and you can watch as the students are working. Sometimes you can even block certain websites or kick them off if they get off task. You should check with you tech person to see if this is available. Another good tip is to make the project exciting or fun. Often times if students are interested and having fun they are more likely to stay on task. Good Luck!