I have Outlook scheduled to start at the beginning of my work day, Monday through Friday. The great advantage for me is that the scheduled task wakes my computer from hibernation (which I choose at the end of the day), and has Windows started and ready for me to log in.

In XP the Scheduled Tasks is in the Control Panel, in Win7 it is under the System and Security and then Administrative Tools, in the Control Panel.

FYI - Adding something to the Startup folder or Schedule does not increase the "boot" time for Windows, as windows has to "loaded" before applications can run, regardless of how they launch.