Not to be lost in the excitement of the Feb 20 swearing-in of Barack Obama as President of the the United States is the day before... Martin Luther King Jr. Day, which very appropriately has had the designation of National Day of Service attached to it.
Below is a clip of future first-lady Michelle Obama discussing the idea of Service on Monday and volunteer opportunities can be found at the at the website http://www.usaservice.org/ and either it's event search page or other service opportunities page.
For an in-depth look at the idea of National Service, there's was a great 2007 Special Report from Time Magazine on the topic.
There's multiple articles as part of the cover story and all can be found under the Time heading "A Time to Serve". Especially compelling, though, is the introductory piece by Time Editor Richard Stengel.