I have used the citronella spray collar (for one of our labs) and it works...for awhile. It works better than the remote ultrasonic collar.
We tried the remote ultrasonic collar awhile back too...the first few times, they heard the noise (all the dogs did), but it seems they didn't care after awhile. But I don't know...maybe that is just my dogs!
Pennies (or marbles, etc) in a can (taped the top) works (sometimes)....and some do the squirt of water too.
I have found that if they get carried away w/ barking..I can whisper and be all happy and they stop and wag their tails and come to get a treat!