www.bnl.com
Lists more than 9,000 mail forwardingservices in the United States.

www.mbe.com
Official Web site for Mailboxes Etc., a national chain of mail forwarding services with more than 3,000 locations.

The Eden Guide to Private Mail Drops
Eden Press
P.O. Box 8410
Fountain Valley, CA 92728
www.edenpress.com
With this book you can find a mail drop almost anywhere in the world. It lists more than 3,000 in the United States, as well as more than 400 in 90 foreign countries.