ArkALMIGHTY offers a free website for each church to coordinate services within their congregation.  Members can post a need for assistance, and other members can view and volunteer in areas they choose.  If you don’t already have an online volunteer scheduling service in your church, you might start out with ArkALMIGHTY.  In addition to helping out members, it promotes congregational support, and allows members to develop relationships with others that they might not have known about otherwise.   

If you have a need outside of your church, within your circle of family and friends, Lotsa Helping Hands is a really helpful site for coordinating volunteer services.