Dried cherries would most likely have preservatives your yeast would not like. Frozen cherries should be available year-round at your local big-box grocery store. If you can't find them, you can use Oregon canned preserves, or in a pinch, cherry pie filling. No extra sanitation steps needed for any of these methods.
You can brew now, and spend the next week trying to find the cherries, as fruit is usually added after primary fermentation. Just remember that the yeast will need another week or two to eat its way through all the sugar in the cherries, and will raise the ABV when it does.