What is the difference between information technology(IT) and computer information systems(IS)?

Information Systems : is a large umbrella referring to systems designed to create, store, manipulate, or disseminate information.
An example of an information system is a pencil and a piece of paper.
The two objects themselves are just tools, but together they create a system for writing (information).
The term Information systems have been around a lot longer than the computer, or the term information technology.
These days the two are sometimes thought to be synonymous, but that, in most cases is a misconception.
Information Technology : falls under the information system's umbrella, but has nothing to do with systems per say.
IT deals with the technology involved in the systems themselves, e.g.
An information system like wiki.answers.com contains many information technologies.
Servers, server operating systems, web-server software (IIS, Apache, et al), and code written for the web-server software (PHP, C#, VB, PERL, Ruby, et al).
Even your computer and browser makes up part of this information system.
Like the pencil and paper example, each one of the mentioned parts of this information system in itself is an information technology.

تكنولوجيا المعلومات يتعامل مع الحواسب الإلكترونية وبرمجيات الحاسوب نظم المعلومات هو عمليات يديوية وغير يدوية ويقوم هذا النظام بمعالجة البيانات والمعلومات

Computer Information Technology refers to hardware (PC's, servers, networks etc) and the associated operating system software (broadly computer software in general can or could be referred to as a form of information technology).
Computer Information Systems are a type of computer software used for the collection of raw data on to which queries can be asked.
The output of the queries would then be termed as Information (and may be presented in the form of pie charts, line graphs etc).

IS-information system means that it works into into your total system and its design of a system on technology.

IT-information technology it works with your technology not only internet and computer.its describe may be into business communication also fro developing business.it cannot be confined into a sector.

Computer Science is the science of computers while Information Technology may or may not use computers.
Of course there is a big overlap but in general computer science handles the technical working of computers whilst IT is concerned more with information manipulation and the business requirements.I think that computer science is concerned with the principles and concepts that are behind the emergence of IT.
In other words, CS is academic studying of the S/W and H/W concepts but IT may have specific purposes to be studied.From a very broad perspective, Computer Science is the study of the principles of computing.
It helps you better understand how computers solve problems, the kinds of problems that a computer can solve and how one would present a problem to a computer.
Abstract ideas that rely on fundamental mathematical theories are at the heart of Computer Science.
Information Technology is the study of technology that drives Information Systems for businesses.
Understanding how technology/tools can best meet the Information management needs of an organization is at the heart of IT.
Familiarity with such tools is an essential for a successful IT professional.
The interesting relation between the2 fields lies in the fact that more often than not, it is Computer Scientists that design and develop these tools that an IT professional uses.
Personally, I think that an adaptable Computer Scientist should not find it difficult to migrate to the field of IT (if he/she chooses to do so) by learning more about the technology that is predominately used at his/her organization.
An IT professional on the other hand, will have to go through mathematics/CS training in order to be a goodcomputer scientist.
In a nutshell, Computer Science is about understanding generic concepts,whereas IT is about knowing more facts.As a computer Scientist migrated towards Information Technology I can say that a computer science is the study of computer's design and operation.
But Information Technology is the use of the computer for a specific purpose without knowing the details of how the computer is carrying on all these tasks.