what he said...
colder liquid absorbs and holds CO2 more readily.
and you can indeed chill it, carb it, and then pull it outta the fridge for storage if you had to. as long as the keg seals well it'll stay carbed just fine this way.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10