Our approach is similar to Estelle's except that our board members have a two year term limit. It's a violation of our by-laws for any one person to continue in the same board position beyond that time.
We begin our nomination process at the end of February. First we poll our current board members and ask if they are planning on coming back. Then early march we post on our website & in newsletter the openings. Typically, we don't get several people come forward -- would be nice but it usually comes down to a recruiting approach. Our nominations chair then starts the process of calling people. When ever possible we push the co-chair approach. Divide and conquer. Seems to work. If we don't have people in slots by April - mid we put our another call for volunteers in our NL & site. Would love to hear from other schools about how they "recruit". Kind of a painful process for us and we are in a school with high parent involvement. E