While a financial statement audit's purpose is to evaluate whether an organization is adhering to standard accounting practices in the development and presentation of the financial statements of the organization, the purpose of an IT audit is to evaluate a computer system's internal control design and effectiveness. (From Wikipedia, with modifications…)
In accounting and auditing, internal control is defined as a process affected by an organization's structure, work and authority flows, people and management information systems, designed to help the organization accomplish specific goals or objectives. It is a means by which an organization's resources are directed, monitored, and measured. It plays an important role in preventing and detecting fraud and protecting the organization's resources, both physical (e.g., machinery and property) and intangible (e.g., reputation or intellectual property such as trademarks). (From Wikipedia, with modifications…)