Here is a binary. It's just the dynamic lib so if you need a static lib and/or the include files (to build against) you should get the source and follow the instructions for building it on windows.
FFMPEG is a multi-platform library (originally on Linux) that allows for the compression and decompression of many audio and video formats. There is a version of blender that is built with the FFMPEG library support, but I think it's only on Linux right now. It should be possible to build the same version Blender on Windows, but you will need the windows version of the FFMPEG library that I linked below. I don't think anybody has done that yet. Does anybody have a windows build of the FFMPEG branch of blender?