I have a 94 sonoma that I just replaced all the brake lines on. My question is, how long would it take to get the air out of the lines? I have bled the lines 3 times already and the brake light still comes on and the pedal is spongy.Any help would be appreciated.

 

when you bleed your brakes start at right rear,then left rear,right front then left front working from farthest point to the master cylinder to closest point.this will eliminate all air but unless you have a reclaimer be prepared to go through some brake fluid

 

Mike,
I'm not going to insult you and tell you to make sure you close the bleeder screws before you let pressure of the brake pedal, but I will tell you that it wouldn't be the first time this has happened where the person opening and closing the screws and person pushing the pedal are not communicating.
Other than that it may be time for a new master cylinder. You may have inadvertently blown the internal seals out of it. Especially if it is old this is very easy to do, if it was replaced and is a remanufactured one just as easy. The best way to check for this is to look for moisture around the brake booster, but I that isn't necessarily the deciding factor.
So Mike, if you open the bleeder screw with the pedal down and you get straight fluid (no bubbles or air) this would be the next step.