People Search is one of the most beautiful feature in SharePoint Server product and this has been enhanced a lot in the 2010 release. But to have this working, first we need to configure User Profile Services and this can be very difficult if you have not done it before.

Here are the steps you need to remember to do the same: http://www.sharepoint24x7.com/2011/01/configuring-user-profile-services-in-sharepoint-server-2010/