//need to add: AVFoundation.framework

#import <AVFoundation/AVAudioPlayer.h> 

NSBundle *mainBundle = [NSBundle mainBundle];

NSURL *url = [NSURL fileURLWithPath:[mainBundle pathForResource:@"game" ofType:@"mp3"] isDirectory:NO];

AVAudioPlayer *gameSoundTrack = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];

[gameSoundTrack prepareToPlay];

[gameSoundTrack play];