Preparing for Interviews Using LinkedIn
Why?
    Anything you do that is one step more than  your competition, puts you a GIANT STEP closer to your new job.
  Surprisingly, most job  seekers will merely show up for the interview as scheduled, with very little  preparation.  You are smarter than  that!  Using LinkedIn to prepare for the  interview is one of those giant steps. 
How?
  Interview Prep #1
  Always research on LinkedIn  every person with whom you will be interviewing, and when you have a specific  time arranged with a specific person, send that person(s) a LinkedIn  Invitation; in the invitation box, add "I look forward to meeting with you  on ________." 
  
  Then during the interview,  let them know you have read their information by saying something like “I was  on your LinkedIn profile, and you have outstanding recommendations.”  Or,  “I read that you have been here at ABC Company for 12 years – this must be a  great place to work.”  Or you may see a hobby, common interest, or other  topic to mention.  Don’t worry that they may see that you have read their  profile; they will be impressed with your thoroughness. 
Interview  Prep #2
  Using the Advanced People Search feature on LinkedIn, locate a current or former employee of the  company who can give you inside information on the company culture or  values.  This person may know the Hiring  Manager or HR Recruiter and can give you tips on what to expect and what to  say.   
Interview  Prep #3
  Again using the Advanced People Search feature, search for someone who previously held the title or position for which you are interviewing. If you have a connection to them and can contact them, you  can gain much useful information to relate during the interview.