Backup to Flickr for iPhoto takes your iPhoto / Aperture library and backs it up to Flickr, keeping your structure intact (iPhoto event is a Flickr set). Choose your iPhoto (or Aperture) collection, push a button, and the app will do all the hard work for you. Thanks to new 1Tb massive storage Flickr gives for free, all your events will be stored in Flickr as sets (albums).
You can also use the opportunity to share with friends and family. Or keep them private.