After you've created a new task or opened an existing one, click the Reminder check box in the Tasks window.
Type the date to be reminded in the Reminder field or click the down-arrow button and choose a date from the minicalendar.
Type the time for the reminder to be displayed or click the down-arrow button and choose a time.
Click Save and Close.
You can set up Outlook to remind you when a particular task is scheduled or due. Because every task may require different lead times, you can select the date and time for your reminder.
Select Alert Sound
If you really want to get fancy, you can change the sound that is played when an alert is displayed. Click the Reminder Sound button and then click the Browse button. Change to the drive and folder that contains the sound file you want to play. Select the file and then click Open. Click OK.