Really simple process:
  • Upload photos to Flick
  • View photoset
  • Click 'Slideshow' in top right hand corner
  • In slideshow view, click 'Share'
  • Cut/copy 'embed' code
  • Paste into Drupal node
  • Select Input Format 'Full HTML', or whitelist the necessary object tags for one of your existing formats
Here's a demo of what it looks like: A wander around Austin, Texas