One organization that is working to make Oakland better is Habitat for Humanity East Bay. I've volunteered with them for coming up on 14 years. They've built decent, affordable housing to give families a hand up for 20 years, and have built over 200 homes around Alameda and Contra Costa counties. There have been homes in Fruitvale, West Oakland and the two large developments south of the Oakland coliseum on 105th Avenue and Edes Avenue. These are good, solid homes, and the more recent ones are built using various green building techniques and include solar panels from PG&E. The partner families work hard, along side staff and volunteers, to complete 500 hours of sweat equity and to help build their homes, and pay a mortgage like other home owners, so these people are invested in their homes and in Oakland. You can read about the dedication of the more recent group of homes here (PDF of the story from SFGate.com).
Habitat East Bay also runs a ReStore, selling new and nearly-new construction materials. If you're doing some remodeling, or just repainting a room, check it out for some low-cost materials. There's a nice piece about the Habitat ReStore on Channel 7 news.
One of the great parts about volunteering with Habitat for Humanity is that you don't need any experience. When I started volunteering with Habitat, I barely knew how to swing a hammer. Over the years, various people have taught me a ton about construction (enough that I designed, permitted and built an addition to our house myself). And yes, Habitat is having a Day of Service event for MLK Day prior to Obama's inauguration.
What organizations do you work with that are making Oakland better?