Seam Carving in AS3, with source02 Sep 2007
Like Hector Yee (whose writeup was very useful), I decided to try an implementation, but in Actionscript 3.
The attached demo only resizes images vertically, not horizontally. I wish I could have, but didn't bother including a dynamic image loader. It's also, well, very pokey, but the code is readable and the output seems accurate. If you can stand the wait, press [M] a few times to load up the seam calculation queue.
If you're interested in a more fully-realized online demo of seam carving, here's one that's been done in Java.
Update: Additionally, as it turns out, Patrick Swieskowski has already put up an online seam carving Flash demo here.