Project Management Information System. An information system consisting of the tools and techniques used to
gather, integrate, and disseminate the outputs of project management processes. It is used to support all aspects
of the project from initiating through closing, and can include both manual and automated systems.
PMIS is part of Enterprise Environment Factors, which are tools, for example project management tools like MS-Project or any other automated tool which can make the Project Management activities easier for the project manager.
Like in some organizations, every project need to use their internal Defect management system, it is another example for PMIS.
Now about Information Management System, definition as per PMBOK5,
Information Management Systems. Facilities, processes, and procedures used to collect, store, and distribute
information between producers and consumers of information in physical or electronic format.
For details of Information Management system, refer pg # 306
An information management system provides a set of standard tools for the project manager to capture, store,
and distribute information to stakeholders about the project’s costs, schedule progress, and performance. Some
software packages allow the project manager to consolidate reports from several systems and facilitate report
distribution to the project stakeholders. Examples of distribution formats may include table reporting, spreadsheet
analysis, and presentations. Graphic capabilities can be used to create visual representations of project performance
So basically Information Management system is related with communications methods and tools which can be used by the Project Manager for project's communication management