Organizations that welcome Volunteers - Here are just a few of the many organizations that could use volunteers.
Click on the link of the organization that most interests you. 

Start with your school. Duplicating, tutoring, reading to classes for as little as 30 minutes a week, and even picking up trash around the campus can improve your school. (My school's website - Lakeside High School, Hot Springs, Arkansas)
Your church would welcome assistance in answering the telephone, typing, cleaning the sanctuary, teaching classes, and helping with programs such as Vacation Bible School. (My Church's website - First United Methodist Church, Hot Springs) 
Hospitals need candy stripers, aides, and volunteers to rock newborn babies and deliver newspapers to rooms. Fundraisers are an excellent way to give money, also. (Local hospitals - Arkansas Children's Hospital, Little Rock; National Park Medical Center, Hot Springs; St. Joseph's Mercy Health Center, Hot Springs) 
Boys and Girls' Clubs always need people to coach sports teams and mentor young student athletes. Cleaning the grounds, running the scoreboards and helping in the concession stands are great ways to get involved, too. (Boys & Girls' Club of Hot Springs website) 
Libraries appreciate people who are willing to file books, assist visitors, and help with the reading and computer programs. (Garland County Library website) 
First Step School of Hot Springs is one of my favorite places to visit. It is a school for mentally and physically disabled students. I enjoy volunteering at First Step School and interacting with the kids. (First Step School website) 
  KARK Community Service
Clinton School of Public Service
Ouachita Baptist University Videos

Volunteering on a national level - Contact these national organizations if you would like to become a volunteer: 

The American Red Cross is an organization that helps victims of disasters in the United States and other countries. Recently, we have all witnessed the efforts of this organization during the Tsunami disaster.
The American Cancer Society 
The American Heart Association 
The Salvation Army

"You give little when you give of your possessions, it is when you give of your heart that you truly give." Anonymous