Looking for a Keyboard Macro / Stuffer

I have Leopard and I'm trying to find something that will let me assign a Key combination to spit out a signature or other text onto the current page.

I've searched here without much luck, but I may not be calling it by the name it would be in the Mac World. In the past, on the PC, I've used programs that let you assign macros or actions to a key. It looks like you can assign some menu options to key combinations in Mac OS X, but I'm not having much luck figuring out how to assign text output to the keyboard.

This can be a native Mac OS X feature or a third party tool. Anyone have any suggestions?

The option for Auto correction and Text Substitution is available in iWork'09 Pages and other software.
Have a look at Automator app. in Finder > Applications and then there is Apple Script available in the same place to play with too.
S.