NSString *mp3one=[[NSBundle mainBundle] pathForResource:@"1" ofType:@"mp3"];
NSString *mp3two=[[NSBundle mainBundle] pathForResource:@"2" ofType:@"mp3"];
NSData *oneData = [[NSData alloc]initWithContentsOfFile:mp3one];
NSData *twoData = [[NSData alloc]initWithContentsOfFile:mp3two];
NSMutableData *data = [[NSMutableData alloc]init];
[data appendData:oneData];
[data appendData:twoData];

self.player = [[AVAudioPlayer alloc]initWithData:data error:nil];
[self.player play];