Freon, itself, isn't really cold. It just happens to be a liquid/gas that can be cheaply compressed (which releases heat) and expanded (which soaks up heat). Having a compressor and coils in a notebook seems impracticle.
Liquid cooling, in this case, is just using the inherent heat capacity of the coolant to carry the heat away. The heat moves from the hot thing (the chip) to the coolant, where it's carried away and cooled off at a more leasurely pace, or an accelerated pace, such as a car radiator.
Air cooling works just the same way, but it has a far less heat capacity and a much slower heat transfer (hense, tons of fins - more surface area = more 'paths' for the heat to move). As pointed out, you can just jet the air out the back and be done with it.
If they use liquid cooling they'd need some sort of radiator to get rid of the heat (which, ironically, will almost certainly be air cooled anyways). The question is, where? I've always thought that the back of the laptop lid has a ton of unused surface area. They could pump liquid up into the lid where it would have plenty of time and space to cool down. Who cares if you have a warm lid.
But, unfortunatly, to pump a liquid straight up in the air 12 inches would require a pretty beefy little pump, so we may not see that method. Of course, they could move the entire processor up there and give it it's own environment. Situated vertically, the processor could heat up the coolant which would naturally rise, lava-lamp style. Maybe a small pump to assist the convection currents. The keyboard part of the laptop would then contain only the much cooler stuff like the drive. Might even make room for a PCI slot.
Or, a 5.25" floppy drive.
Hmm - i should get back to work.