I assume everybody who is interested has found out by now, that you can subscribe to Flickr RSS feeds with the new iPhoto ’06 to have them show up as what Apple calls Photocast. The bad thing about it is that several infos are lost and mainly the feed only contains the small images.
A witty macosxhints user has reacted immediately and set up a little web application to convert the Flickr feeds for subscribing in iPhoto ’06, check it out below:
Thank you 3eyes (John Evans)
thanks to Jason who pointed me in the direction of a very similar service, with a few extra features, called photocastr.