systems operate within systems.
IS is an integrated set of components for collecting, storing, processing, and communicating information. Business firms, other organizations, and individuals in contemporary society rely on information systems to manage their operations, compete in the marketplace, supply services, and augment personal lives. For instance, modern corporations rely on computerized information systems to process financial accounts and manage human resources; municipal governments rely on information systems to provide basic services to its citizens; and individuals use information systems to study, shop, bank, and invest. (http://www.britannica.com/EBchecked/topic/287895/information-system)
Information is the critical ingredient for the operation and management of any organization.
Information systems (IS) is a coordinated collection of information subsystems that are rationally integrated to collect, store, process, retrieve, disseminate, and communicate information for the support of operations, management, and decision-making functions in business and other organizations. The objective of IS is to enhance productivity by improving the efficiency and effectiveness of business processes. (further > http://www-afa.adm.ohio-state.edu/u-majors/pdf/infosys.pdf )
Information systems (IS) is a coordinated collection of information subsystems that are rationally integrated to collect, store, process, retrieve, disseminate, and communicate information for the support of operations, management, and decision-making functions in business and other organizations. The objective of IS is to enhance productivity by improving the efficiency and effectiveness of business processes. (further > http://www-afa.adm.ohio-state.edu/u-majors/pdf/infosys.pdf )
Information systems emphasizes the application of information technology in business and other organizations. Computers and other information technologies are the technical foundations or the tools of information systems. However, both technical skills and knowledge of business processes and practice are needed to be able to properly envision, design, implement, integrate, evaluate, and manage computer-based solutions to business problems.
The goal is to produce solutions that transform data into information and knowledge that is useful for individuals and organizations.
A business is an 
organization comprised of multiple workers, interdependent in the tasks they perform.
http://docs.globaltext.terry.uga.edu:8095/anonymous/webdav/Information%20Systems/Information%20Systems.pdf
organization comprised of multiple workers, interdependent in the tasks they perform.business functions
Specialized tasks performed in a business organization, including manufacturing and production, sales and marketing, finance, accounting, and human resources.
The business model is simply a working description that includes the general details about the operations of a business. The components that are contained within a business model will address all functions of a business, including such factors as the expenses, revenues, operating strategies, corporate structure, and sales and marketing procedures.
image is taken from http://www.telco2.net/blog/2007/05/the_telco_20_methodology_busin.html
