To answer your questions,
Yes, but it will probably be flat unless it's a well sealed container and there's sufficient fermentables to produce CO2.
If it wasn't sealed well, yes.
Yes it is

but kegging is great.
Seriously, if you are considering kegging, and have the fridge/space/permission then go for it. It's so much nicer just to get and get a beer with just a flick of the wrist. No more bottles to clean, store etc (although you can/should always bottle a few of your better beers to share or take to the mates).
Have a look at a few of the HBS in your area, most of them either supply or can point you to a good supplier of kegging systems.
Trev
(about to go out and pour another glass form the serving fridge)