None of this is particularly hard, just time consuming. It is well worth it, though, to use fresh cherries. Get a friend to join you, and make a morning of it.
Equipment
Smoothie straws
Cutting board
Plenty of towels
Paring knife
Instructions
Start by pulling all the stems off your cherries and giving them a good washing with cool water. Drain the water off and gently pat them dry with a clean dishtowel.
Cut your smoothie straws in half. You'll need quite a few straws because they do tend to break after about ten cherries. Center the hole of the straw over the center of the cherry (where the stem once lived), and push the straw all the way through to push the pit out.
Keep the pits and stems separate from your cherries.
Once you've pitted all the cherries, begin slicing them in half with a paring knife.