The easiest info to find may be the positive PR info disseminated by the company--digging up any "dirt" may be a bit more difficult.
You can get the "company side" of the story using resources on this page. Use additional links on the left for ways to find criticism and/or less biased sources on a company's social performance.
Check the company web site to see if they have a section of the site on social performance. Look to see if your company publishes a Corporate Social Responsibility report (CSR report). CSR reports can be called by other names such as a Corporate Citizenship Report, Sustainability Report, Environmental Report, etc.
If you don't find the report on the company web site, try the CSR Collection sites in the box further down on this page. You might also try a Google search to find the report--Example: exxon "social responsibility"
If you are looking for a CSR report on a specific company, you may find it on the company's web site. The sites below are useful for browsing reports from many companies.
How does your company's giving compare?