Upgrading to 4.0 I quickly realized it was gone.
http://forums.getpaint.net/index.php?/topic/25598-does-anyone-use-the-freeform-shape-tool/ Turns out no one uses it.
I use it a lot for quick drawings/sketches.
http://imgur.com/OPTUVk8 || An example (I've done many more)