is an image cropping jquery plugin that will satisfy your needs and much more

I can still remember the old digg.com user profiles with dynamic avatar cropping via JavaScript. Their user interface was clean, easy to use, displayed a sample before you cropped, and would auto-update as you changed the selection box. I have always admired this design and have been on the lookout for a great jQuery plugin which can offer similar features with less custom code.

After toying with Jcrop I have come to really support this plugin. The codes are very small and do not require a whole lot of setup (although there are plenty of optional settings). My demo example will include dynamic avatar updating in real-time, along with a PHP rendering script. I think the amount of new social networks and websites offering user profiles should definitely take this UX technique into consideration.