It is well worth your time since the experience will greatly assist you later in obtaining a summer or full time position. You will also find that volunteer work is a very rewarding experience due to the great appreciation from those you are working with and those you are assisting. PILF's Pro Bono Project organizes law student volunteer projects within the community. Each semester they have a fair that brings in over 20 community organizations seeking volunteers for both legal and non-legal assistance. Time and length commitments vary per organization.
Most job positions are subject to budget constraints or approvals.
Thus, while some employers will be looking in the fall, many positions may not come available until the spring and summer. Timing is very important in this field because by the time the budget is approved the agencies are rushing to fill open positions. Get in contact with employers early and remain in contact until they actually have an opening with funding approval. These positions put you in a stronger competitive position to get job offers and perhaps grant money. There are a variety of internships or fellowships available for students to participate in and gain valuable work experience.