Regional

Separated by location of organization.

United Way - Find your local United Way to post opportunities and find volunteers. Many locations throughout the state, Wisconsin, Iowa, and the Dakotas.
2-1-1 Minnesota - Find information for community services, health and disaster information, child care, senior services, counseling, food, shelter, job services and more in Minnesota. 

Metro:
Hands On Twin Cities - Recently updated online database with up to 8,000 metro area volunteer opportunities. 
Community Thread - Stillwater, serving the St. Croix River Valley

Northeast:
United Way of Greater Duluth Volunteer Center - Provides searchable database containing volunteer positions, trainings, and community events in northeast Minnesota and northwestern Wisconsin.
Arrowhead RSVP - Retired Senior Volunteer Program, Located in Virginia. Serves St. Louis, Cook and Lake counties
Volunteer Services of Carlton County - Located in Cloquet

Northwest:
FirstLINK - Located in Fargo, serving Fargo/Moorhead area
Heart of the Lakes United Way - Located in Alexandria. Serves Douglas County

Central:
United Way of Central Minnesota - Located in St. Cloud
United Way of West Central Minnesota - Located in Willmar

Southern: 
United Way of Olmsted County - Located in Rochester

National

AmeriCorps - With the recent expansion of the program, there are more AmeriCorps members than ever! These dedicated men and women donate one year of their life to volunteering. To find out how you can apply for an AmeriCorps member placement at your organization, see the AmeriCorps organization page.

Volunteer Match - Operated by Impact Online. Register your nonprofit/organization to recruit volunteers in your area. (Same database as the AOL Foundation: www.networkforgood.org

Engage Volunteer Network - Simple web application that helps volunteers find opportunities in their community. Within the online network, they can find and share opportunities, see what volunteer projects their friends are working on, and track activities.

Youth Service America - Provides opportunities to search organizations, volunteer, advocate, and get connected.

JustServe.org - A platform where volunteers and organizations connect. There's an app too! It is free to post volunteer needs and there are local specialists in each state to help you get started.

iParticipate - Volunteering website created by the Entertainment Industry Foundation. With their recent volunteering storylines on TV and massive ad campaign, this website is creating quite a bit of buzz. 

International

Idealist.org - Volunteer database that is operated by Action Without Borders. Provides volunteer listings, nonprofit searches, jobs and more.

International Volunteer Programs Association - Located in New York City, this organization links volunteers with projects across the globe. Volunteering without boundaries!