The link is to the Facebook FAQ on the new profile.
If you choose to apply the new profile, you cannot revert back.
None of the privacy settings are changed. But, there are some new things to be aware of regarding privacy (tagged photos at the top of your profile, and any special friend lists you add to Relationships that will appear on the left of your profile to anyone who can see your "Friends List" - both of these items are listed below in the highlights).
Tabs that went across the top are now items on the left side.
New: Additional fields of interest, graphic display for top interests, more ways to list how you spend your time
To post on your wall, see near the top: Share: Post, Photo, Link, Video to choose which type of thing to share.
To edit your profile, click the Edit Profile button in the top right corner.
To remove any pictures that appear at the top from appearing at the top, roll over the photo and click the X in the top right corner. This does not delete the photo, it just removes it from appearing at the top of your profile.
If you want specific friends lists (that everyone can see just like your regular Friends list) to appear on the left of your profile, choose Edit profile, Relationships, and next to Featured Friends, choose to add either an existing friends list or create a new one.
TechCrunch: Full details on Facebook's overhauled profile pages
Inside Facebook: Facebook profile redesign will coax more data from users: an in-depth review
Craving Tech: Facebook introduces your new Profile page. Like/Dislike?