In Outlook 2002, it is
Tools-Options-Email Options-Tracking Options-
Checkbox "For all messages I send..."
You can request a Read and Delivery receipt.
This is in 2002, so different version may be slightly different, but
it will be in Tools Options Email Options.
Keep in mind, the recipient can have it set to prompt them whether
they want to send the receipt(s), so you may not get accurate results.
My approach would be to include the phrase "Please let me know when you read
this." in a signature. It would be no less reliable than a read receipt
request.