Public companies usually have an investor website separate from their more commonly seen homepage. These sites are fairly easy to find via your favorite search engine and include things like quarterly and annual reports, news releases, shareholder meeting information (minutes, videos, etc), as well as other information essential for investors.
To find a company's investor page simply search your company's name + the words, "investor relations."
For example, when I Google, apple investor relations, I get this: http://investor.apple.com/
Here are links to several companies' investor pages that students often choose: