Vatican
United States Conference of Catholic Bishops
Catholic Conference of Ohio
Catholic Foundation (Ohio Not for Profit Organization)
Catholic Information Network
Catholic News Service
Catholic Engaged Encounter
Catholic Campus Ministry
Catholic Report
Coming Home Network
Cum Christo
Movie Reviews
COURAGE
North American Conference of Divorced and Separated Catholics
The Catholic Pages
The Pontifical College Josephinum
Knights of Columbus Supreme Council
National Association of Catholic Family Life Ministers
Retrouvaille (Rediscovery) International
Columbus Legion of Mary
Worldwide Marriage Encounter
Catholic Men's Ministries 
Catholic Women's Conference
St. Gabriel Radio
St. Joseph Adoration Monastery
Mother Angeline McCrory Manor
Villas at St. Therese
Disciples Now
Once Catholic 
Active Parishioner 
Lay Cistercians of Gethsemani

The 2009/10 Diocese of Columbus Directory is a great resource!
View here.