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.
Many companies file annual reports with info on environmental performance and/or positive social impacts. Often called a Corporate Social Responsibility Report (CSR), Environment Report, Sustainability Report, or similar title--these reports might be posted on the company web site, sometimes in the investor relations section of the web site.
Many companies also send out press releases about positive social efforts.
To find unbiased info on social performance, you may need to look at sources that don't originate with the company--such as the Responsible Shopper site or articles in news sources that don't rely entirely on press releases.
For more in-depth advice, see the guide for MGMT 480 - Social Audit of a Company.