>>85
こんな感じで。
aSound と repeat はインスタンス変数。

-(IBAction)play:(id)sender{

[aSound release];
aSound=[[NSSound alloc] initWithContentsOfFile:@"/System/Library/Sounds/Glass.aiff" byReference:YES];
[aSound setDelegate:self];

repeat=YES;
[aSound play];
}

-(IBAction)stop:(id)sender{
repeat=NO;
}

-(void)sound:(NSSound *)sound didFinishPlaying:(BOOL)aBool{
if (repeat) [aSound play];
}