Your question may appear to have nothing to do with Wikipedia (the category in which you put it); however, the wise observer sees why a question about IMDb-like software may actually belong in the Wikipedia jurisdiction. The reason?
Did you know that the popular movie site IMDb.com is owned by Amazon, and you can buy Amazon products directly from IMDb pages? Well, surprise surprise -- there are over 285,000 links to Amazon's IMDb site from Wikipedia. Furthermore, Amazon particularly invested $10 million in Wikia, Inc., which was co-founded by the founder of the Wikimedia Foundation that owns Wikipedia. Thus, Jimmy Wales is potentially helping to insure that the external linking environment on Wikipedia is hospitable for the Amazon/IMDb link spamming! See how the money circle works?
But, to really answer your question, I see that IMDb utilizes the Open Graph Protocol in its source code, so you might want to start your search for IMDb-like page code there. Also, don't miss the Open Source Web Design project.