Outlook 2002 (XP)

Unless you have access to the account the email was sent to, in order to log in and delete it from there, there is no way to "unsend" an already sent email. Sorry.

-Dave

Recall or replace a message you've already sent

This feature requires Microsoft Exchange.

You can recall or replace a message only if its recipient is logged on and using Microsoft Outlook and has not read the message or moved it from their Inbox.

If the Folder List is not visible, click the View menu, and then click Folder List.
Click Sent Items.
Open the message you want to recall or replace.
On the Actions menu, click Recall This Message.
Do one of the following:
Recall the message

Click Delete unread copies of this message.
To be notified about the success of the recall or replacement for each recipient, select the Tell me if recall succeeds or fails for each recipient check box.
Replace the message

ClickDelete unread copies and replace with a new message.

Click OK, and then type a new message.

To be notified about the success of the recall or replacement for each recipient, select the Tell me if recall succeeds or fails for each recipient check box.

Note To replace a message, you must send a new one. If you do not send the new item, the original message is still recalled.