And now for your input stuff, you can use a simple 10K - 22K resistor in serie for sure. OR use a 7.5K in serie + 5.1K resistor to the ground as a voltage divider. It ensure to have a better "ground" or "0" reading.

In another hands, i still don't understand why those BasicStamp are still on the market. To Expensive for what we can do with...