You'll need to schedule the execution of a template that runs queries and based on the results sends some emails.
The tags for that template are a seperate issue... but to setup a routine for automatically having CF server access the template you'll need to use a very advanced feature called CF Scheduler in the Administrator pages:
YourWebserver/cfide/administrator/
Under automated tasks you can setup scheduled tasks. You can create a custom method using the tag CFSCHEDULE to allow people other than admins create tasks, but for your uses, as long as you have access to the admin section you can setup a task.
Task has: name, type, date span, and interval
Name is whatever you name it. The type is usually HTTPrequest (its just hitting whatever .CFM). The date span is from whatever date to Indefinitely or to another date. And the interval is every 5 minutes, every 1st of the month.. etc.
As I said, the code for the template to execute is another matter.
Don't you love CF!?