Cherry lovers are lucky. Two of the best cherry varieties, the Bing and the Ranier, are widely available in grocery stores and markets from mid-June through early August (fruit picked earlier than this tends to be small, medium red and tasteless). Look for firm, plump, glossy fruit, large and dark for its variety (Bings will have dark purple to mahogany skins and the Rainier has a golden skin with a pinkish-red blush).
Make sure they are still attached to green stems. Refrigerate cherries that will be stored for more than a few hours, but don't wash them until you eat them; to enjoy the best flavor, take them out a half-hour before eating them.
Sour cherries, widely used for cooking, are a separate species. Few are sold fresh. Michigan usually grows about three-quarters of the American crop. If you're travelling this summer, visit Traverse City, MI "The Cherry Capital of the World" to celebrate the National Cherry Festival from July 5-12th.
Some mail-order sources for for top-quality cherries:
Mission Orchard - 800-289-4114
Harry and David - 800-547-3033
David's Selected Bibliography for Cherries
Bader, Myles H., Cherry Creations: The Ultimate Cherry Cookbook, Las Vegas, 1995
Brown, Susan K., et al., "Cherries," in Fruit Breeding, volume 1: Tree and Tropical Fruits, edited by Jules Lanick and James Moore. New York 1996.
Hedrick, U.P., The Cherries of New York, Albany, 1915
Leroy, Andre, Dictionnaire de Pomologie, Tome V., Paris, 1877
Marshall, Roy E., Cherries and Cherry Products