Our CSA box always includes a newsletter from the farm. This week they mention that cilantro is one of the few herbs that does not retain its flavor when dehydrated, but that you can freeze the fresh leaves in a ziploc. Just remove the air, seal the bag, and freeze. They point out that you shouldn't thaw them before use or they'll turn into a mushy green mess. Since we don't use cilantro very often, I think I'll give it a try.