I know that Seed Planters Supply in Huntersville carries them, but I'm not sure if they would at this time of year. You're looking for red wigglers. Sometimes you can find them at stores that carry fishing bait. But you have to check for red wigglers in particular, not the big earthworms. Hope this helps.
I know that the NC Wildlife Federation over at 2155 McClintock Road does worm composting workshops in schools... you may call and see if they can recommend a place, or share some of the worms from their bins