Well you can either go over and have a polite chat with them or you can let it stew and make you angrier until you get to the point where you finally break and do something stupid (many stupid suggestions have been made already..death etc.).

They may not even realize the dogs are barking for various reasons hard of hearing, thick walls, general tuning out of their own animals noise (I can't hear my dogs most the time myself). So be polite and let them know that their dogs excessive barking at night is getting out of hand and offer them some options on how to control it (bark collars etc.). If they refuse let them know that you will be forced to call the city and file complaints if it continue *only if they refuse or are unreasonable*.

If you haven't approached them then you can't expect them to know there is a problem.

Oh yeah and you should check your local ordinances about noise because around here from 6:30AM to 10PM there are no enforceable laws about noise.