News about a company can come from news organizations (television, radio, print, internet) or from the company itself (press releases). If the company is publicly traded, a press release will almost always be duplicated via an SEC filing (form 8k, or "current report"). You can find company press releases on the company's website and 8k filings in any database where you find other SEC filings (such as annual or quarterly reports).
The web offers a variety of comprehensive financial news sites that provide important up-to-date business information about companies and industries as well as links to both domestic and international business news and financial market research. The resources below are a non-exhaustive list of such sites.