1001
Mac OS X application for uploading and notifying you when new photos are added to streams you want to watch.

Flickr Rainbow
Displays most recent images from all the users at Flickr which have been tagged with the colours of the rainbow.

flickReplacr
Bookmarklet to swap a flickr pic for that word.

Kubrickr
is a tool that lets you replace that giant blue blob at the top of your WordPress 1.5 blog with a nice photo from Flickr.

Flump
Simple application that allows your to download all of the public photos for a specific Flickr account.