We don't charge for volunteers and PSAs. Just go into the handy dandy Volunteers Needed Announcements section (
http://somd.com/announcements/volunteers/) post away.
The best method of getting volunteers is to have current volunteers personally recruit. It's easy to ignore a PSA but when your friend comes to you and says they could use your help, you're more likely to do it.
Volunteering is a great way to make new friends and get involved with your community. That's one of the things I miss about down there - me and all my friends volunteered in some fashion. And I'm being lazy up here because I know that if one of my neighbors came up to me and asked me to come help man the soup kitchen or cart meals to the elderly, I'd do it in a minute. I really should just contact someone and start doing more instead of waiting for them to come to me.