Purging a keg

So tomorrow Im going to bottle a batch and keg a batch but I don't bottle where my kegerator is. Thusly I want to detach my co2 tank from the keg thats already carbed, take it home and purge the keg that I fill tomorrow and bring it back home and hook it back into the keg in the kegerator.

So with that said:
a) is it going to cause a problem to leave a the keg that is carbed in the kegerator unhooked from the gas for a few hours, and

b) does anyone have a link to a tutorial on purging kegs of o2, it seems pretty self explanatory, just wanted to make sure I understand the process,

Much appreciated.

a) No problem at all. Unless the keg has a leak it will remain at the same level of carbonation. It's just like a big bottle.

b) There's no real tutorial necessary. Hook up the gas and then pull the pressure relief valve for a few seconds.

I read somewhere to open the CO2 and wait until you hear the air stop rushing. Then, purge - and repeat 3 or 4 times.

Thanks for the quick answers guys, now I can sleep assured and slightly innebriated!