Ok guys....just found out how to do this so I thought i might as well share it as i know a few of you are on macs and flickr
> Ok so first think to do it choose your desired photostream and copy its address, for example mine is
http://www.flickr.com/photos/richwigley/> Next, go to
http://www.bigflickrfeed.com/ and enter your flickr photostream URL, choose either "Feed my most interesting photos" or "Feed my latest photos" and then click GO.
> Copy the address that the website gives you, mine is
http://www.bigflickrfeed.com/photos/richwigley/>> Now into System Preferences on your mac.> Click Desktop & Screen Saver and select the Screen Saver panel.
> On the left hand side click on the + button and click "Add RSS Feed"
> Paste the
http://www.bigflickrfeed.com/photos/richwigley/ (in my case) URL into the box, wait for it to validate and then click OK.
> Set the Display Style to slide show.
> Click options and make sure that the Random and Cross fade boxes are ticked to make it look nice!
DONE!
Rich