In SharePoint 2010, people search crawls are not added to the content source sometimes and if you dont see people results, there are a couple of things that you need to check.
Ensure that the user profiles are crawled. To do that go to the search settings page and click on manage content sources - (It’s under Central Administration –> Service Applications –> Search Service Application –> Manage button) Click on content sources..
If an address starting with sps3 does not exist, then add it of the format sps3://intraneturl (where intraneturl is the url of your default intranet site).
Once that step is done, permissions need to be granted to the search crawl account to crawl the content.
To do that, go to the Service Applications page, click on the tab User Profile Service Application, do not click on the link but just highlight that line and click on the "Administrators" button at the top of the page. This will show a window where admin users can be added..If the search crawling account does not appear then add the account to the window and choose the permissions "Retrieve People Data for Search Crawlers" from the permissions list check box. If this step is not done, an access denied message will be shown in the SharePoint 2010 crawl logs.
Once the above steps are done, full crawl of the content source needs to be done after which the people search will bring back results.