The Internet Movie Database (IMDb)

I have used this site quite often myself, finding movies that have been out in previous years, learning about their tag lines, and reading their reviews. I have found it very helpful in many cases and have watched a few movies I would normally not have seen because of it. Also, I have used it to find names of actors and actresses of different movies and looking at other movies they've worked in. For all you movie buffs who want to learn about any particular movie, it is the place to go.

I absolutely love IMDb too and use it all the time to look up information about movies.