How can I introduce my new kitten to my 8-year-old black Labrador Retriever?

We tried last night. We confined our dog to the kitchen, and put a gate between the kitchen and the hallway (across an archway), with a cat-sized hole underneath. We allowed the kitten to come out of my room and she slowly walked up to the dog. She remained by the gate for awhile, hesitant and hissing at the dog. Then, the dog looked up, and she walked through the hole, right past the dog! Fortunately, we were able to grab the dog before she saw the kitten (what an ignorant doggy we have, lol) and all was well. But our kitten seems to show no restraint in meeting the dog.

We considered putting the dog in a kennel and allowing the cat to come up to her, but the dog is powerful and can break through the kennel. We considered holding her on a leash, but no one is strong enough to overcome a strong dog with lots of willpower.

I'm not sure about the relationship ever developing…you implied that your dog only wants to chase the cat, which is slightly out of character for labs, but nonetheless…. It's possible that they'll never be acquainted.
I have a german shepherd (naturally aggressive dog) and although he grew up around our two cats, he still bites at them. I fear you may be in the same situation.
However, like I said, he is a lab, so he should be able to adjust. I'd suggest doing the barrier thing, except neither the dog nor the kitten should be able to get through. The more their associated with each other, the better.
I'm quoting:
"I know two people that have labs and cats. Incidently, in both families the labs were full grown and the cats were introduced to them. Both of these labs get along great with the cats. IMO, as long as the puppy (regardless of breed) is raised with the cats it will learn to get along fine. I had 2 adult cats and 1 kitten when I brought home my aussie mix puppy. She used to try and herd them and play with them. If they wanted to get away from her they were able to jump up out of her reach. Now she is full grown and cuddles with the cats. They all get along great and love each other."

The general opinion is that the labs will get used to it. Good luck.