If you're read tech news whether it is to keep up or researching new companies, Tech Crunch is a valuable resource. On TC each article about a company has in-depth information on the right side column. It links over to Crunch Base just click on the company title and you'll open up a whole chronological history of the founders, funding they may have received, investors, acquisitions and changes within the organization.

For the full info and additional research you should get the pro subscription that allows drilling down into companies, key players, websites, domain names and more. It has a nice java interface, looks like it was built with DHTMLX, but more than likely a custom cut. Well worth the subscript for professionals.