Phew, I just found it - I don't know where to put it.
I'm guessing that you've posted trying to find it because an install of some other app errored out saying that it could not find it. What was the error? Where was it looking for it?
Most other lib files will be located in either /usr/lib/ or some other lib directory deeper down. Depending on your error you should be able to locate what lib directory it goes under if not in /usr/lib/
. . . and remember to update your libraries once you've copied it over - for the life of me I can't remember the command!