An information technology audit, or information systems audit, is an examination of the controls within an Information technology (IT) infrastructure.

An IT audit is the process of collecting and evaluating evidence of an organization's information systems, practices, and operations. The evaluation of obtained evidence determines if the information systems are safeguarding assets, maintaining data integrity, and operating effectively to achieve the organization's goals or objectives.
These reviews may be performed in conjunction with a financial statement audit, internal audit, or other form of attestation engagement.

IT audits are also known as automated data processing (ADP) audits and computer audits. They were formerly called electronic data processing (EDP) audits.

http://en.wikipedia.org/wiki/Information_technology_audit