If you often send similar email messages, perhaps you use the same subject, body or recipients, you might consider creating an Outlook message template. They work similarly to Word's templates. The method is simple:

Outlook 2003

1. Set up your message the way you want it appear: recipients, subject, body, or signature.
2. Select File -> Save As... from the menu.
3. Choose the location, e.g. My Documents, to save the template.
4. Select Save as type: and change it to Outlook Template (*.oft)
5. Click the Save button.

Outlook 2007

1. Set up your message the way you want it appear: recipients, subject, body, or signature.
2. Click on the Office button and Select Save As -> Save As.
3. Choose the location, e.g. Documents, to save the template.
4. Select Save as type: and change it to Outlook Template (*.oft)
5. Click the Save button.

The new template will appear in the location you saved it with the name you gave it and have the extension OFT.
The extension may not be visible if you have Windows Explorer configured to hide extensions on known file types.

You can use the newly created template by opening Windows Explorer, navigating to the location and double-clicking on the template.  An Outlook message window will open with your pre-configured information ready for you to complete and send.

N.B.: Neither XP's Outlook Express nor Vista's Windows Mail have this feature.