Foldr Monitr
Free tool that runs in the background and watches a selected folder (and optionally subfolders) waiting for you to add photos to it. When photos appear in the folder, Foldr Monitr automatically uploads them to your Flickr account for you.

Phlogre
Photo Organizer for local photos and flickr photos. Meant to replace the official Flickr Uploadr.

Flishr
Windows application to Download, Upload and Search photos from one central command console on your PC.

Flickrfs Virtual Flickr Filesystem
Create a virtual userspace filesystem which allows easy uploading/downloading/searching of images through flickr.

KFlickr
A standalone Flickr.com uploader for KDE

Flickr Importr
A tool for Windows that allows you to upload images to Flickr and automatically add them to groups and sets.

Flidget
A dashboard widget for tiger that allows you to upload your photos.

Grabbr
A small application to smooth the task of uploading screenshots to Flickr.

Flickr .NET
A .NET wrapper for the Flickr API. Allows desktop and web applications to provide direct image upload functionality to Flickr and its services.

jUploadr
A cross-platform uploader for both linux and windows.

Photoupload
Image uploader to flickr. Upload photos directly to photoset, Use IPTC and EXIF fields in photo description, and generate tags from IPTC keywords.