Lefty, Thanks for that info but there must be a way to disable that pull-up????
As AB posted above the soft pull-up is optional and not enabled unless you do a digitwrite high after setting the pinmode to input. However not setting the pull-up does not ensure that the pin will assume a digital low if left unconnected. It will be floating and subject to switching logic levels with noise, tides, time of day, etc... 
Again, to insure a low on a unconnected input pin there must be an external pull down resistor installed.
Lefty