I am looking for good PhD students most of the time. The most important prerequisite to be successful in machine learning is a strong mathematical background.
If you are interested, please do not apply to me directly, as all applications are centralized through the department. However, you can shoot me an email and let me know that you submitted your application (so that I can make sure I won’t miss it.) Please indicate on the application that you are interested in working on machine learning. All students who are accepted will obtain a fully funded fellowship that covers tuition, 12 months salary and health insurance. (Please don't send me any emails with questions about the application process, as I am not involved in it.)
Concrete information on how to apply is here.
(Before coming to Cornell, I used to be part of the machine learning group at Washington University in St. Louis. You may want to apply there, too - they have a great group.)