This work deals with the problems of company‘s client managament system developing. The survey of Outlook 2003 possibilities has been presented in the work. New program features have been considered and advantages of the program have been examined in comparison wiht the previous versions. A comparative analysis of Outlook 2003 and other e-mail programs (Outlook Express 6, Pegasus Mail 4.21c, Eudora 5.0.2) has been carried out. A new Microsoft automation technology has been reviewed and applied to the developed client managament system. It allows to integrate the work of several programs and ensure system effeciency and flexibility. The experiments devoted to investigation of e-mail message sending time dependancy upon the number of recipients and message size have been carried out.