Setting outlook calendar reminders

Is it possible to use asp.net to create a calendar reminder in outlook?

I am using .N开发者_运维技巧ET 3.5 and have MS Outlook 2003.

If this is possible, how can this be done?

It can only create a calendar reminder in the Outlook that is installed on the server machine. It can't create a reminder in the Outlook of the user that is using your application, because it runs in the sandbox of the browser.
If you want to create the appointment on the server, have a look here: http://www.codeproject.com/KB/cs/outlookappointments.aspx

Update:
After you clarified that you are using an Exchange server, you can use the EWS Managed API to create an Appointment. I haven't used it myself, so I can't help you any further.