Add app to Login item. http://cocoatutorial.grapewave.com/tag/mac-os-x/ + me

LoginItem.m

-(void) addAppAsLoginItem {
    if ([self wasAppAddedAsLoginItem]) return;
    
	NSString * appPath = [[NSBundle mainBundle] bundlePath];
    
	// This will retrieve the path for the application
	// For example, /Applications/test.app
	CFURLRef url = (__bridge CFURLRef)[NSURL fileURLWithPath:appPath];
    
	// Create a reference to the shared file list.
    // We are adding it to the current user only.
    // If we want to add it all users, use
    // kLSSharedFileListGlobalLoginItems instead of
    //kLSSharedFileListSessionLoginItems
	LSSharedFileListRef loginItems = LSSharedFileListCreate(NULL, kLSSharedFileListSessionLoginItems, NULL);
	if (loginItems) {
		//Insert an item to the list.
		LSSharedFileListItemRef item = LSSharedFileListInsertItemURL(loginItems,
                                                                     kLSSharedFileListItemLast, NULL, NULL,
                                                                     url, NULL, NULL);
		if (item){
			CFRelease(item);
        }
        CFRelease(loginItems);
	}
}

- (BOOL)wasAppAddedAsLoginItem {
    NSString * appPath = [[NSBundle mainBundle] bundlePath];
	CFURLRef url = (__bridge CFURLRef)[NSURL fileURLWithPath:appPath];
	LSSharedFileListRef loginItems = LSSharedFileListCreate(NULL, kLSSharedFileListSessionLoginItems, NULL);
    
    BOOL ret = NO;
    
	if (loginItems) {
		UInt32 seedValue;
		//Retrieve the list of Login Items and cast them to
		// a NSArray so that it will be easier to iterate.
        
        CFArrayRef loginItemsArray = LSSharedFileListCopySnapshot(loginItems, &seedValue);
        
        for (id item in (__bridge NSArray *)loginItemsArray) {
            LSSharedFileListItemRef itemRef = (__bridge LSSharedFileListItemRef)item;
            //Resolve the item with URL
			if (LSSharedFileListItemResolve(itemRef, 0, (CFURLRef*) &url, NULL) == noErr) {
				NSString * urlPath = [(__bridge NSURL*)url path];
				if ([urlPath compare:appPath] == NSOrderedSame){
					ret = YES;
				}
			}
        }
        CFRelease(loginItemsArray);
        CFRelease(loginItems);
	}
    
    
    return ret;
}

-(void) deleteAppFromLoginItem {
	NSString * appPath = [[NSBundle mainBundle] bundlePath];
	CFURLRef url = (__bridge CFURLRef)[NSURL fileURLWithPath:appPath];
	LSSharedFileListRef loginItems = LSSharedFileListCreate(NULL, kLSSharedFileListSessionLoginItems, NULL);
    
	if (loginItems) {
		UInt32 seedValue;
		CFArrayRef loginItemsArray = LSSharedFileListCopySnapshot(loginItems, &seedValue);
        
        for (id item in (__bridge NSArray *)loginItemsArray) {
            LSSharedFileListItemRef itemRef = (__bridge LSSharedFileListItemRef)item;
			if (LSSharedFileListItemResolve(itemRef, 0, (CFURLRef*) &url, NULL) == noErr) {
				NSString * urlPath = [(__bridge NSURL*)url path];
				if ([urlPath compare:appPath] == NSOrderedSame){
					LSSharedFileListItemRemove(loginItems, itemRef);
				}
			}
        }
        CFRelease(loginItemsArray);
        CFRelease(loginItems);
	}
}