You can update your profile to the new look by going here and clicking the “Get Timeline” button, or you can wait for an announcement to appear at the top of your profile. You can also refuse to switch to the new look until Facebook inevitably decides to switch your account over sometime down the road–at which point you can shout “Zuckerberrrrrg!!!” while shaking your fist at your monitor, threaten to quit Facebook and then keep using Facebook.
If you make the switch now, you’ll have a seven-day period with which to preview all the changes, promote (and hide) various bits of your content and adjust various privacy settings.
According to Facebook’s blog post:
When you upgrade to timeline, you’ll have seven days to review everything that appears on your timeline before anyone else can see it. You can also choose to publish your timeline at any time during the review period. If you decide to wait, your timeline will go live automatically after seven days. Your new timeline will replace your profile, but all your stories and photos will still be there.
If you want to see how your timeline appears to other people, click the gear menu at the top of your timeline, and select “View As.” You can choose to see how your timeline appears to a specific friend or the public.
