Although the app is targeted at companies or project managers, OrgChartWiki is very well at helping you out with someone else : Map your client's organization.
any organization, why not use it to map the knowledge you have about a client, or, more interesting, a possible client, and make it worth you while ? It will easily show you the gaps in the knowledge you currently have about the company you're interested in so you'll know how to target them.
I think weve got a pearl in hiding here....