Apple has pulled the update. If you haven't installed it yet, don't. If you did install it and can't boot, you'll have to boot into Lion Recovery mode and reinstall (you won't lose your files or apps).
18 ways to view the ~/Library folder in Lion
Macworld, awesome as usual. One trick I didn’t know, especially useful when using a computer that’s not your own:
Hold down the Option key while clicking the Go menu, and your Library folder magically appears.