Apple has hidden the user Library folder by default in Mac OS X Lion. These are instructions on how to make it visible again.
Launch a new Terminal window from your Applications:Utilities folder.
Type in chflags nohidden ~/Library/ into the Terminal window and press Enter.
Voila, your Library folder will now appear in your Finder window.
NOTE: If you don’t want to permanently make the Library folder hidden you can also just hold downOption and click the Finder Go menu to reveal a quick link to the folder.