5 answers
There is a section on tasks for reminders... A Checkbox and Date/time. You can select if it's on the day of, day before, and what time.
http://na15.salesforce.com/help/doc/en/activities_setting_reminders.htm
Salesforce can display popup reminders for upcoming tasks and events. Reminders notify the activity assignee of an upcoming task or event. The reminder displays in a small browser popup window when the activity assignee is logged in to Salesforce. When a user logs in, any reminders that have not been dismissed and reminders scheduled to occur since the last time the user logged out are shown in the reminder window.
When you create or edit an event or task, you have an option to set a reminder on it. The reminder defaults to the time specified in your reminder settings.
To set a reminder on a task:
Create or edit a task.
Select the Reminder checkbox.
Choose the date and time for the reminder. You will be reminded of the task on that date and time.
If you are setting the reminder for a recurring task series, the reminder applies to each occurrence in the series.
Click Save.
To set a reminder on an event:
Create or edit an event.
Select the Reminder checkbox.
Choose how long before the event that you want to be reminded.
Click Save.
