This is a rewarding step. Some parents may not have the time or the inclination. But often hesitation stems more from lack of confidence. Tell the teacher how much time you have and that you'd like to help, but don't know what you can do. Chances are, once you make the effort, the teacher will find something that plays to your strengths.
Some schools have guidelines for the amount and types of assistance that parents can give.
Check with the school principal or a PTA officer if those regulations need to be clarified. When middle school rolls around, teacher communication becomes trickier. In addition, the kids are changing as much as the school environment. Although children at this age may seem less willing to have their parents involved, participation is still important and recommended. Parents can continue to communicate with the school, but they must know where to start.