Signatures are even handier than templates in so far as I use them more often. They are like templates, but are used for emailing. This is where Microsoft Outlook becomes a great tool.
You will have no doubt seen the standard disclaimer messages on the bottom of emails before.
There is no limit to what you can do as a Signature. I use mainly three, one as a 're-order form' another as a 'cost reply' and the third as a standard disclaimer. Once installed you can use them over and over again.
I create them in Word and when I'm happy how they look I select everything on the page and copy, then I open Outlook and paste them into the Signatures dialogue box, saving each Signature with its own name.
You can download some examples in the downloads section.