Zen Practice for Inmates 
Meditation training as an alternative to conventional sentencing. During the past year a "scholarship" fund has been created to assist serious inmate practitioners in attending a monastic training period on parole or at release from prison. The Engaged Zen Foundation intends to establish a monastic-based alternative sentencing facility where offenders may serve out sentences in a highly disciplined Zendo atmosphere.
http://www.engaged-zen.org/Gateless Gate Prison Outreach Program 
Florida prison effort of the Kwan Um School of Zen.
http://www.gatelessgate.org/prison/prison.htm
Prison Dharma Network 
A nonsectarian Buddhist support network for prisoners, prison volunteers, and correctional workers. An affiliate of the Buddhist Peace Fellowship.
http://www.prisondharmanetwork.org/
Angulimala - the Buddhist Prison Chaplaincy Organisation 
Organisation representing Buddhism in the prison service.
http://www.angulimala.org.uk/
Shambhala Prison Community 
Initiates Buddhist meditation groups in US prisons and jails.
http://www.shambhala.org/int/spc.html
Buddhist Relief Mission 
Prison Dharma Support system of the Buddhist Relief Mission.
http://www.brelief.org/prison.htm
Kanromon 
Meditation group meeting at Baltimore City Detention Center.
http://homepage.mac.com/bdgzendo/prison.html
Shambhala Prison Community 
Serves spiritual and educational needs in prisons.
http://www.shambhalaprisoncommunity.org/
Prison Dharma Support 
A non-sectarian Buddhist support network for prisoners, prison volunteers and correctional workers.
http://www.greatliberation.org/activities/prisondharma/pds.htm
Buddhist Inmate Sangha 
An interfaith group of Buddhists devoted to connecting prisoners who desire to learn about Buddhism with pen pals of their respective faiths. Provides books on Buddhism and Eastern Philosophy to inmates and prison libraries upon request.
http://nichirenscoffeehouse.net/bis/index.html
National Buddhist Prison Sangha - Zen Mountain Monastery Prison Program 
Volunteer organization. Depending on their experience with practice, as well as their time and personal resources, these volunteers may provide support through correspondence, visits, and the creation and leading of practice groups.
http://www.mro.org/smr/prisonsangha/