fuddland has this article posted on using "a Flickr feed to include any photostream on your site via PHP and MagpieRSS".

Cutting to the chase: I've knocked up a PHP script which takes any Flickr photostream RSS or Atom feed and makes a Flickr "badge" out of it, with some extra bits thrown in to make it all worthwhile.

Download the script. Edit it and fill in the required details. Upload it to your server. Cross fingers. [You'll also need MagpieRSS. Grab it, extract it, stick it somewhere on your server. No need to change any of its settings. Just remember where you put it so you can tell the Flickr script. Oh, and create a writable directory for the cached feed.]

They step you through the process, giving you which items you need to change in the script to make it pull the content that you need from Flickr...