YES ! YES! YES! u can do it.
Use Microsoft Outlook 2003 or Office XP Outlook 2002.
Step 1: Compose any message you want to send. (Configure Outlook to allow you to edit your e-mail in MS-Word)
Step 2: Click on the
Options... button
Step 3: From the dialog box that appears put a tick on
Do not Deliver before and enter a post dated date and time.
*img164.imageshack.us/img164/5889/mail32go.th.png
Step 4: close the dialog box.
Step 5: click on the SEND button.
Now your message will remain in the Outbox folder and will automatically be mailed to the recepient on the date that you specified on the Do not Delive before field. Provided you go online daily and check your mails using Outlook.
How is it helpful ?
Suppose you are forgetful, just want to send a birthday wish to your wife back home, and you always forget to do so. Then using this method you will never forget to wish your wife in time again. Good luck.
Note: I just discovered this a few minutes ago.