why are A0 & A1 always high even when i have nothing connected?

i'm useing an ethernet shield SD on a arduino mega 1280... however whenever i have it connected A0 & A1 read high, why is this? also what is the maximum size the micro SD card can be and still function with the shield?

Do a little research on floating pins, its perfectly normal on very high impedance inputs as used on the Arduino. If you want it to read low, you could connect a 10 k resistor between Gnd and the pin you want to read low (whats known as a pull-down resistor).

i connected an led from each pin (seperatly) then to ground. the led lit up as if the pins were shorted... are they?

also i'm using an Arduino brand, version 2 shield

i guess that makes sense... what about the max size of the sd card?