This paper describes some preliminary results from a 20-week study on the use of Compaq iPAQ Personal Digital Assistants (PDAs) by 10 senior developers, analysts, technical managers, and senior organisational managers. The goal of the study was to identify what applications were used, how and where they were used, the problems and issues that arose, and how use of the iPAQs changed over the study period. The paper highlights some interesting uses of the iPAQs, and identifies some of the characteristics of successful mobile applications.