As you know Flickr is an online application help you upload, store, catalog and tag you photos. You could get the comprehensive, first-class and effecient photo service from it. This is why the Flickr is very welcomed by people now. Of course if you are a programmer then you will be interested by the flickr library an ActionScript 3.0 API which provides access to the entire Flickr application. Following is the dowload URL and tutorial for it. Why not see it at once?
URL on Google Code: http://code.google.com/p/as3flickrlib/
The tutorial: LoginProcess Shows how to login to a Flickr account using the API.