Web-based matching services like www.volunteermatch.org and www.serve net.org hook up would-be volunteers with the local organizations that need them. If you don't feel you can commit to a regular schedule of community service, you can participate in so-called "episodic" volunteering—from service-oriented vacations (try www.globalvolunteers.org or www.transitionsabroad.com) to school break alternatives for high school and college students (www.habitat.org/ccyp/cc.html).
The Internet even provides opportunities to volunteer in cyberspace through the latest development in civic engagement—virtual volunteering. Virtual Volunteering Project (www.serviceleader.org) tracks a variety of Internet volunteering opportunities. And iMentor (www.imentor.org) matches students with adults for mentoring relationships that take place primarily through e-mail.
Or simply try calling an organization that interests you and asking what you can do to help. You'll be hard pressed to find anyone who will turn you down.
