This document announces a call for papers for a special issue of the ACM Transactions on Intelligent Systems and Technology (ACM TIST) on intelligent multimedia systems and technology. It seeks papers on machine learning and data mining techniques for understanding, indexing, searching, and consuming the large amount of multimedia data available online and on mobile devices. Topics of interest include intelligent systems for multimedia data management and search, content understanding of images, video and audio using machine learning, social media analysis, and large-scale learning algorithms for multimedia. Papers will be peer-reviewed and the special issue will be published in two parts, with submission deadlines in February/April 2010 for the first issue and April/May 2010 for the second issue