Mac OS X 10.7 Lion hides the /user/Library folder from the user by default.
Accessing this folder can be done by going to the Finder Go–>Go to Folder and tying it in there. Holding down the Option key while clicking on the Go menu will show as a menu option there as well. For a more permanent solution the following Terminal commands will unhide and hide the folder.
chflags nohidden ~/Library/
chflags hidden ~/Library/