Is there any web site out there that documents director's cuts vs the originals?

[TVC15]

I am watching the DC of Hellboy right now, and I was curious what was added over the theatrical cut.  Director's Cuts have gotten so popular since the dawn of the DVD era, so I was wondering if there was any site or resource available that documents the differences between the different cuts of a movie.

It would be pretty useful, and really interesting.  For example, there are at least 7 different cuts of Mr. Arkadin. There are 3 or 4 cuts of Brazil.  3  Blade Runner cuts.  And now, just about anything major has a different cut for the DVD release.

[Ichirou]

Doesn't DVD Beaver cover those things? 

I know there's some sites that cover director's cuts/theatrical cuts by genre and nation (the Euro version of Once Upon A Time in the West vs. the US version, for example), but I dunno if there's a site that covers every single movie that's ever had an alternate version released.

[The Fake Shemp]

The Director's Cut offers more insight to Rasputin and kind of fleshes out the fact that he didn't come back in just plain human form, that he's some kind of vessel.  It also explains how the creatures were able to replicate in the sewers and whatnot, it was a bit ambiguous before.  It also gives us a couple more Liz shots.  Not a ton of stuff was added, but it fixes some plot holes that existed before.

[Polari]

IMDb sometimes have pretty detailed notes in the "Alternate versions" section of a movie's page.