Running ASP code in the background

Hi there..
>
I have a ASP web application, in the application I need to check if people
did submit some documents, and if they don't past a certain date I want to
send them email notifications.
I am using SQL Server 2000 and SQL Server Agent
How can I write ASP code to run in the background on my IIS server, that
will check for people who did not submit past a certain date and
automatically send them email notifications?