Searching the Web
e.g.: search for "Microsoft" within ".edu" sites
Another great search tool is IPL2 (formerly the Librarians' Internet Index)
This libguide will provide access points to relevant information in order to help you create your business plan for Professor McGinnis. Below is the Free Business Plan Sample website - click on it to explore other business plans.
You can learn a lot about companies by going to their own web sites. Bear in mind there will be a particular bias which you can balance out by using other published sources.
If you want to explore other websites about them, use the box to the right (Web Searching) to do an advanced search on them or their products/services.