a cool dry dark place (cupboard) is best, if they are properly sealed (air tight) tho they should be fine in the fridge. i'v heard people say cracked grain can last upto 3 months without any bad effects if properly kept, i'v never kept cracked grain longer than a month tho personally
I've kept it for close to 9 months and still smells as fresh as and no sign of moisture damage what so ever, poured smoothly from the bag into the scales.
A grain mill is definately a worthwhile investment though check the craftbrewers link and they are dirt cheap. After a few bulk buys of grain the mill pays for itself