We have just added two twelve week old ragdoll kittens to our family. They are socialized and are fine with everyone except out 9 year old kelpie/cross.
She is okay with them but won't look directly at them as they hiss every time she is about. What can we do to help them bond with her.

As far as them bonding with your dog, it will just take time. Cats are territorial animals and any strange dog (or strange cat, for that matter) is considered a trespasser and a threat. The dog has a different scent which they will have to get used to. Luckily the cats are young, which means that they should be used to the dog within 1-2 weeks or less, but be prepared for it taking as long as 6 weeks in some cases.

The most important thing is to not force contact. Make sure the dog and cats have their own space. Since the dog is okay with them, you don't have to worry so much about the dog being overly excited or playing too roughly with them. But if that should ever happen, make sure the cats have an escape route and something high to climb on, to get away from the dog. A cat tree is ideal.

If you have a big room, such as a large kitchen or family room, you can try doing pleasurable activities with the cats while the dog is present but at a "safe" distance. Playing with the cats, grooming them if they like it, and feeding them treats are all good examples. The dog can get groomed, played with, or given treats in the cat's presence too. This will help the cats to associate the dog with pleasant things.

Be assured though, that even if you do absolutely nothing, the cats will definitely grow to tolerate and probably like the dog within a 6-week period. It just takes time and patience.

Hi!
There's one more thing I'd like to add to Chava's wonderful answer:
Cats are solitary animals, while dogs are by nature animals who like to live in "herds".
That's why, dogs will welcome a cat in their territory, but a cat, even a young kitten, has to adapt to the idea.
We had two female Beagles, and when they were 1 year old we got an 8 weeks kitten. The dogs adopted her on the spot, and were constantly trying to lick their fur, which she, (an appalling thing from her point of view) - she kept hissing for a while, but it didn't take much for her to sleep purring "attached" to their bellies.
Good Luck,
Millie

Thanks for the replies. I'm feeling a bit more optimistic. Already one of them is getting more relaxed around her. (only the occasional hiss now) The other boy is going to be the hard one but I'll be patient.

Hi, ragdolls,
You have received two very good answers.
I would just like to re-emphasize about not doing anything, to force them to get together.
Once the kittens are comfortable with the dog, they will probably be playmates!
A friend has two dogs, and 5 cats. All became friends within about 5 weeks.
Best of luck.