you cant read analog values on digital pins. you can however use external parts to attach more than one analog input to your boards analog inputs, and read them one at a time.
this playground article shows how to use a 4051 multiplexer chip to read 8 analog values with one analog pin and 3 digital pins. looks like its just what you need.
The Arduino's based on the surface mount version of the ATmega168 have 8 analog inputs. The seeeduino is a popular version with 8. I think the Arduino nano also has 8.
If you must use a Duemilanove, there are analog multiplexer ICs or separate analog to digital converters you can use. But you can't read an analog value on a digital pin (otherwise why distinguish the analog pins?).