We finally moved our first all grain batch to keg and it's in the kegerator at 12PSI which is what I use when I get store bought kegs. Do I need to turn up the CO2? Shake the kegs? Leave it and drink next week?
For next time, try getting a carb stone for your keg. Several places sell them, I have the .5 micron diffusion stone that AHS sells in all of my kegs. You can carb in a couple days at serving pressure. Works great.
I usually set it and forget it for about 2 weeks at my serving pressure. I usually get good results but the diffusion stone would also work and faster too I'm sure. Also I have hooked the gas up on my liquid out post and that seems to work a few days faster. Just make sure you have check valves so you don't have beer go back into your regulator.
No, you can use it for kegging too. After all, a keg is really just a big bottle if you think about it. The key is to add the priming sugar (usually about 2.5 ounces) and then let it sit at room temperature until it's carbed up, just as you do for bottles.
There are several ways to force carb. My best results come from sticking the keg in the fridge at 12 psi for 10 days or so, although it gets better for up to two weeks. But sometimes I'm in a huge hurry, so I'll set the regulator to 30 psi for 36 hours, then purge and reset at 12 psi. It's pretty well carbed in 3 days that way.
I'm not a fan of shaking, or of setting it higher for longer, as those tend to be the problem kegs (foaming, poor head retention, etc). If you're a patient person, 12 psi in the kegerator for 2 weeks is probably the "best" way to do it.
You can use priming sugar if you'd like. Lots of people naturally carb in the keg because they don't have extra CO2 lines, and they don't want to wait a week or two for it to force carb.
Priming sugar is another method of carbinating, but this is done at room temperature and takes around 2 weeks. If sone this way be sure to take a sample prior to placing in the fridge ao you know you have the right carbination level in the beer. This is because the yeast will go dormant once it is cooled down to fridge temp so no more carbination will take place. Force carbing is definitely quicker. I have seen no difference in taste either way.