I want to allow people to select a feature region on an image using jQuery. This should work similarly to the Facebook tagger except once someone "tags" an area of the image an ellipse should appear with the ability for the user to rotate and scale it.
How can I achieve this using jQuery?
I would start by looking at jQuery.animate() and also look at animate plugin/patch
I'm not sure about the rotating part, but I've used this in the past for the selection piece:
Makes it very easy to grab the coordinates of the selection (and very clear to the user what they're selecting), when rendering later you could do whatever you desire with the defined area.
In terms of image rotation, take a look at Raphaël -- specifically this demo. Raphaël plays nicely with jQuery.