Max Vernon shows how you can use the SQL Server Agent to send automated e-mails on alerts:
SQL Server Agent provides a great mechanism for sending alerts via email in response to various events. Once you’ve setup Database Mail, and configured a SQL Server Agent Operator, you should add alerts for severe errors that affect the health of your SQL Server. Creating Alerts can be tedious, but automating Alerts is simple, with the easy code below that automates creating alerts in response to critical events. Automating alerts is important because it provides a standardized Alert configuration that can be used by all the SQL Servers in your organization.
Read on for the script.