via Roy Osherove:

Alt+F3: create auto-text entry.
Just select the text and press Alt F3 and you can save the text for future use..

I use Word everyday, and I can see where this shortcut will definitely be helpful for me. The text that you capture becomes available on the Insert --> AutoText menu. If you use Word as your editor in Outlook, then this text also becomes available when creating e-mail messages.