This is an application from Google that tries to locate information about missing persons in Haiti. I don’t know how well it works, but I think Google is trying pretty hard with its considerable resources to find any data that might help.
Update (1-17-2010): News organizations that have set up sites to help locate people are apparently opening their systems and sharing their data with the Google people-finder application. The MIT Center for Future Civic Media is calling on all people-finder data collectors to pool their data in one place. This is very smart and will drastically increase the effectiveness of the Google people-finder app. Here’s more about the call for shared data.