CSE is related with invention and development of of software and hardware whereas IT is related with effective use of already available software/hardware. CSE thinks about how can a new system be developed whereas IT thinks that how can an already available system be put for gainful commercial use. While implementing certain tasks,the CSE ask question about working of hardware & software but IT want to know about the working of office and business systems so that it can modify, improve and educate you to use existing software/hardware.
When you produce the system that control the Rockets, Machines, DVDs, Medical diagnostic instruments etc, that is called CSE and when you learn to improve, implement and manage the given system that is called IT. Computer Science is a subject in general dealing with computer hardware software. IT is a derived subject which is mainly involved in the management of information using computers.
Computer science (academically, CS, CSC or compsci) encompasses a variety of topics that relates to computation, like abstract analysis of algorithms, formal grammars, and subjects such as programming languages, program design, software and computer hardware. Computer scientists study what programs can and cannot do, how programs can efficiently perform specific tasks (algorithms and complexity), how programs should store and retrieve specific kinds of information (data structures and databases), how programs might behave intelligently (artificial intelligence), and how programs and people should communicate with each other (human-computer interaction and user interfaces). Good for jobs like software engineering, hardware engineering, computer science professor, programmer, etc.
While Information technology (IT) is the technology required for information processing. In particular the use of electronic computers and computer software to convert, store, protect, process, transmit, and retrieve information from anywhere, anytime. This is really good for individuals who don't like math because it offer less math courses. You can get jobs such as database administrator, webmaster, programmer, software engineer, telecommunications, management, computer security analyst, etc. The information technology course module has been designed with more of software part in the course whereas Computer Science includes more of computer hardware part like networking, chip level knowledge etc. Although some of the subjects are same in both the streams.
Also CSE is more math intensive than IT. Information Technology is the business side of computers - usually dealing with databases, business, and accounting. The cs engineering degree usually deals with how to build micro processors, how to write a compiler, and is usually more math intensive than IT. One way to think of it is one is dealing with information - data which would be the IT and the other is dealing with the "science" or "how to make it" of computers. So there is very thin line dividing the two streams. There is a lot of overlap in the two streams. In every tough It problem, there is a CS problem.
