This is a queue manager I quickly threw together last night. Basically just manages some dispatch_queue_t objects and organises them based on arbitrary integer keys you pass. Will automatically create queues when requested.

RAPQueueManager.h

#import <Foundation/Foundation.h>

@interface RAPQueueManager : NSObject
{
    NSMutableDictionary *queues;
}

@property (retain) NSString *label;

- (id)initWithLabel:(NSString *)label;

- (dispatch_queue_t)queueAtIndex:(NSInteger)index;
- (void)removeQueueAtIndex:(NSInteger)index;

@end

RAPQueueManager.m

#import "RAPQueueManager.h"

@implementation RAPQueueManager

- (id)initWithLabel:(NSString *)label
{
    self = [self init];
    if (self) {
        self.label = label;
    }
    return self;
}

- (id)init
{
    self = [super init];
    if (self)
    {
        queues = [[NSMutableDictionary alloc] init];
    }
    return self;
}

- (dispatch_queue_t)queueAtIndex:(NSInteger)index
{
    NSNumber *indexObject = @(index);
    dispatch_queue_t queue = queues[indexObject];
    if (queue) return queue;
    
    queue = dispatch_queue_create([self.label UTF8String], NULL);
    queues[indexObject] = queue;
    return queue;
}

- (void)removeQueueAtIndex:(NSInteger)index
{
    [queues removeObjectForKey:@(index)];
}

- (void)dealloc
{
    for (dispatch_queue_t queue in queues)
    {
        dispatch_release(queue);
        [queues removeObjectsForKeys:[queues allKeysForObject:queue]];
    }
    
    [queues release];
    queues = nil;
    
    [super dealloc];
}

@end