If you want a free organizer program on your desktop, then go with Essential Personal Information Manager or EssentialPIM or more shorter, EPIM . I use the software mostly to list my 'to do' tasks which you can order by priority. As David Allen stresses in his bestselling book Getting Things Done, listing down your tasks is the first essential step in being more organized and productive, and EPIM is a wonderful tool to do that.

There's also a scheduler to list down and organize your daily tasks by the hour and you can make notes to yourself. You can compare the pro and free version of EssentialPIM if you're interested in getting more advanced features such as 'Editable categories of tasks and events' or 'Synchronization with PocketPC or Smartphone'.