http://socaltransport.org
try Pomona Transit Center for start location
There is a bus that leaves Pomona for LA @ about 11:20 PM but that may be cutting it close...
I live 5 minutes away from the place in Pomona so I don't have to worry about it, but I also have a ticket for the next night at the Wiltern and I have to figure how to get to there and back to Pomona also....
It sucks not being able to drive...