Cropbox is a lightweight and simple jQuery plugin to crop your avatar.
FocusPoint is a jQuery plugin for responsive cropping. Dynamically crop images to fill available space without cutting out the image's subject. Great for full-screen images.
Image Cropper is a jQuery image cropping plugin with preview and some options.
Croppic is an image cropping jQuery plugin that will satisfy your needs and much more.
Jcrop is the quick and easy way to add image cropping functionality to your web application. It combines the ease-of-use of a typical jQuery plugin with a powerful cross-platform DHTML cropping engine that is faithful to familiar desktop graphics applications