CIRCLIST
A pro-circumcision website aimed at men who would like to be circumcised as adults.
http://www.circlist.com/

Circumcision Resource Center
A non-profit educational research center studying circumcision and recommending against it.
http://www.circumcision.org/

Dick: A User’s Guide by Michele C. Moore and Caroline de Costa, published by Marlowe & Company [Buy]
Written for men and women of all ages, two doctors demystify the penis with a wide range of education about anatomy and function along with advice on safe handling and proper maintenance.
ISBN 1569244294

Erection Photos
Penis photos (non-sexual), flacid and erect, with information on size and shape. Good information for clients who have penis size questions or issues.
http://www.erectionphotos.com