Redirects in PHP

I want to do one of those redirect pages where a php script prints HTML saying "sorry we're not here, we're redirecting you to the right location" and then after about 2-3 seconds a new location header gets printed and you are transported to the new location. I see this everywhere but don't know how it's done. I tried this by printing the "Location" header first and then the text and it just relocated me without seeing the text. I tried printing the text first and then the "Location" header and php complains that my header was already sent and I can't modify it to relocate. How do you do this?? Is there something in the header I have to specify to wait before it relocates? Do I have to do it manually by printing the text.. tell the script to wait and then clear the header somehow and send a new one (can that be done?) I looked at HTTP1.1 docs and I didn't really get anywhere. Any ideas? Carl.