Open Central Administration and navigate to “Manage Service Applications”
In Manage Service Applications select Search Service Application or Enterprise Search Service Application depend on your SharePoint Setup.
In Search Service Application in SharePoint 2010, select Content Sources in your left hand side under Crawling
In Content Source right click on your site and select Edit
check your Crawl status. If you see your current status is Idle, you should start your crawl in order to search people or any contents
Go back to your previous windows and right click on your site and select Start Full Crawl
When crawl completes, you can check the status and crawl log when you right click on your site
If everything looks good, you should able to search people in SharePoint 2010. This is how you enable People Search in SharePoint 2010.
If your still having problem, please see my Configuring profile import in SharePoint 2010