brotherhood_of_LAN - 1:31 pm on Mar 17, 2011 (gmt 0)
You won't want PHP to send any output before the HTTP headers, as per the description in the manual [php.net]
Using the logic you've provided, you may be better off putting it at the top of the page.
if($first_name != 'Jane')
Because you're going to redirect the user, the rest of the page is pretty much obsolete in their case, hence you can put it at the top of the script and let the rest of your code deal with the non-redirected users.