This plugin provides a new "Promote (Expression) To Parameter" Refactoring
It produces the same effect as using "Introduce Local" followed by "Promote to Parameter"
So all it really does is save you a a few keystrokes/ mouse movements. but that's ok, since making you more efficient is what CodeRush and the DXCore are all about.
Select any expression, on which you would normally be able to apply "Introduce Local" and you should see the additional option of "Declare Parameter" in the code section of the CodeRush SmartTagMenu
Core Techniques: Alex Skorkin
Specifically: How to perform an existing refactoring from another one