Rehydrating is a good way to go but consider grinding them. Once ground they are easy to store and use. For extra depth in flavor I add ground anchos to all kinds of things: pasta sauces and meat rubs come immediately to mind.
To grind the anchos, first place them on a cookie sheet in a medium oven until they are brittle and break when bent. Be sure to turn them often so they don't burn. Break the chiles into small pieces and grind in spice mill or coffee grinder.
For recipes and more info on ancho and other spices, have a look at The Epicentre Exotic Herbs and Spices