Time-Driven Alerts
SharePoint alerts are event-driven; they only occur in response to an item being added, changed, or deleted. If you want to send an alert when a deadline approaches, you need to install a third-party web part such as SharePoint Reminder from Pentalogic.
To get SharePoint Reminder:
Download the web part from http://www.pentalogic.net/sharepointreminder.
Install the web part on the server.
Run iisreset.exe to load the changes.
SharePoint Reminder includes free licenses for five web part instances, with five more provided when you register the product. You can purchase additional licenses as needed. Once installed, you enable time-based alerts on a list by completing these tasks:
Create a view of the list that displays the items to send.
Add the SharePoint Reminder web part to the site's home page.
Set the web part properties to watch the view of the list and send mail as needed.
Sending Reminders for Urgent or Overdue Tasks
Use time-driven alerts to send reminders for tasks that are urgent or overdue. For example, to send reminders two days prior to a Due Date in a task list:
Add a calculated column to the task list with the following settings.
Section
Property
Setting
Name and type
Column name
Alert1
Type
Calculated
Additional Column Settings
Formula
[Due Date]-2
The data type returned
Date and Time
Date and Time Format
Date Only
Create a new standard view for the list with the following settings.
Section
Property
Setting
Name
View Name
Urgent
Filter
Show the items when column
Alert1
is less ...