ASP.NET 2.0 includes a new set of features called 'Health Monitoring.'  This involves a lot of different ways to monitor the 'health' of your application in event logs, performance counters, etc.  One use of it, though, is to send email notification of exceptions.  This is something we traditionally had to do in code, or with a logging framework like Enterprise Library Logging.  In ASP.NET 2.0, though, it can be done by simply configuring the application.

This also includes some cool features- such as the ability to prevent sending the same error 100 times.  Other providers support going to a SQL Server table or the event log.