First, there is external communication, be it posters in a store, a tab on a corporate website, or a print advertisement, announcing what the corporation does to be more responsible. A corporation might be taking actions to consume less energy and produce less waste (Subaru). A company might be investing in wind power to off-set it's consumption of coal-based electricity (Brooklyn Brewery and the new Brooklyn Bowl come to mind).
Second, there is philanthropy, which I consider to be all donations to social, cultural and community organizations that are not designed to act as lobbyists nor expected to promote the company in return. So this would include museums, schools (public or private), hospitals, clinics, and all types of private service organizations that are designed to help people who live nearby (think rehab clinics, domestic violence centers, and career counseling and assistance groups (Dressed for Success comes to mind)). Corporations that have an advanced philanthropy structure (like the late Lehman Brothers) eventually set-up a foundation, and invite employees to contribute to it and have a say on which organizations should receive cash gifts.
Third, there is 'community outreach.' This is usually more difficult to organize than the actives above, but it involves having employees volunteer their time to any number of local activities. In New York City, one of the easiest ways to accomplish this is to have employees join a New York Cares project (cleaning parks and public gardens, running clothing drives, consulting non-profits, tutoring students, etc.).
And fourth, there is the kind of community service that might not have been asked of the company directly, but it was in a position to provide a valuable service from its location(s). That's what we're seeing from Minneapolis-based, Target. Since 2006, Target has been experimenting with affordable health clinics in both Minnesota and D.C. I was surprised to find this, and from the looks of it, they are expanding their services to include flu and hepatitis vaccinations.
When going beyond corporate citizenship lip service, a public health clinic can go a long way to prove that Target actually cares about preventive, afforable health care.