Try here:
http://sourceforge.net/projects/gnuw...es/zlib/1.2.3/
You'll need both the bin and lib files extracted to the same place.
You may have to fiddle with the order of the library directories to get it to work properly. MySQL also distributes zlib.lib and if they are not the same version you will have linking errors as you saw. If you put the MySQL directory above the zLib directory it should work.