That was the one I followed, got up and running with it in no time.
Then once I knew it all worked, I got a little more daring with the second schematic in this one so I could get 3 of those pins back.http://code.google.com/p/arduinoshiftreglcd/
You will have to change your program while daring at the shift reg lcd like this:
ShiftRegLCD objectName(Datapin, Clockpin, Enablepin or TWO_WIRE [, Lines [, Font]])
where Lines and Font are optional.
* Enablepin: can be replaced by constant TWO_WIRE, if using only 2 wires.
* Lines: 1 or 2 lines (also 4-line LCD's must be set as 2).
* Font : 0 or 1, small or big font (8 or 10 pixel tall font, if available).
You can't use LiquidCrystal lcd(blah) any more.
Are you really in need of three pins? Have you used the analog pins as digital pins?