After uploading a few photos to Flickr and realizing how quickly that 10MB/month upload quota was going away, I realized that I would have to resize my photos before uploading them. So, rather than crack open Photoshop, I did what any other programmer would do. I wrote a program to resize and upload for me. It's actually pretty sweet and quite functional. Check it out if you have a (free) Flickr account.
You should know: The error handling is pretty thin. It preserves EXIF! It won't save your login/password (not necessarily bad). It's multithreaded; I think you'll like it. I'm actually happy with the architecture! I wrote it in one evening.
Edit 2005-02-12 16:30: New version, 0.9. Better error handling, supports drag-and-drop, saves login/password if desired (Base64 encoded in "HKCU\Software\Pettijohn.com\FlickrShrink"; not really secure, but obfuscated a bit), remembers last folder you added files from, creates thumbnail in a background thread (gives a nice UX when you select amongst items in the upload queue), mores little fixes.