I recently started aging beers in kegs. I did this with my strong winter beers the end of August and have my winter warmer on tap now. I think it tastes better than when I aged it in a carboy last year.
I take a clean sanitized keg, fill w/ some CO2 to purge any oxygen, fill the keg, purge, and let sit in the basement to age at about 17 psi. Once it's ready to go into the kegerator, I connect it up, release the CO2 and set the psi at serving pressure. Ready to go in about a week. Not sure if this is the perfect way to do it, but it has worked for me so far.