The University of Maryland International Music Competitions, Maryland Center for the Performing Arts, seeks volunteers to house contestants for the third Marian Anderson International Vocal Arts Competition and Festival, which is being held at the University of Maryland at College Park through Saturday. Volunteers will provide accommodation and transportation for 40 international contestants and will receive a limited number of complimentary tickets to competition rounds, festival recitals and the competition finals concert with a performance by the Baltimore Symphony Orchestra at the Kennedy Center. Additional volunteer opportunities include ushers for daytime and evening events, office assistants and drivers. For more information, call 301-405-0383.

Calvary Women's Shelter needs dinner, evening and overnight volunteers for its 25-bed shelter for homeless women. For more information, call Carrie at 202-783-6651.

NASA'S Goddard Space Flight Center in Greenbelt seeks volunteers to be tour guides, front desk information aides, office assistants and presentation assistants. For more information, call 301-286-9041.

The Law Foundation of Prince George's County seeks volunteer Spanish to English translators with court experience and/or Maryland court certification. For more information, call Neal Conway at 301-864-8353.

Pets on Wheels needs volunteer visitors to share their calm, people-loving pets with socially isolated, frail and mentally impaired individuals who often have few or no visitors. For more information and referral, call Elaine Goad at 301-853-3330.

Artrain, the nation's only traveling art museum on a train, seeks volunteers to serve as guides during its five-day visit to Washington. The key roles of volunteer guides are to welcome visitors and to help them better understand the exhibition. Volunteers are needed 9:30 a.m. to 3 p.m. today through Friday, and 9:30 a.m. to 1:30 p.m. or 1 p.m. to 5:15 p.m. Saturday and Sunday. To volunteer or to get more information, call 1-800-278-1971, Ext. 233.

CASA of Maryland seeks volunteers to become basic-level computer instructors to teach computer skills to as many as 10 students with little or no previous computer experience. In addition, Spanish literacy tutors are needed to tutor adult Spanish speakers in the basics of reading and writing Spanish, as well as math, and an ESL instructor is needed to teach basic-level English to adults once a week for eight weeks. For more information, call Naomi Nim at 301-431-3721.

The Crescent Cities Center in Riverdale Park seeks volunteers to provide friendly visits, one-on-one sessions and exercise groups; read to residents; deliver mail; run the gift shop; and perform numerous other services. For more information, call Monica Greene at 301-209-6421.

Bethel House, a welfare-to-work program in Brandywine, seeks volunteers to fill a variety of positions, such as assisting instructors with daily course work, mentoring, performing clerical duties and facilitating a class. For more information, call Maria Carrasquello at 301-209-5020.

CHADD, whose mission is to improve the lives of people with attention deficit and hyperactivity disorders through education, advocacy and support, has an ongoing need for volunteers to help with fund-raising, data entry, receptionist responsibilities, accounting and general office work. For more information, call Stacy Ramos at 301-306-7070, Ext. 114.

Marietta Mansion in Glendale seeks volunteers to assist in the gift shop on weekends. For more information, call 301-464-0590.

If you would like to volunteer, please contact the agencies directly. If you would like to submit a notice for Volunteers, fax to 301-952-1397; e-mail to pgextra@washpost.com or write to Volunteers, Prince George's Extra, The Washington Post, 14402 Old Mill Rd., Suite 201, Upper Marlboro, Md. 20772.