I did chocolate dipped cookies last year for the first time, and just bought the chocolate wafer things from the bulk food store (the round ones occassionally with nipply bump things for doing chocolate moulds and such) boiled water, but the double boiler pan thing on top, dumped in my chocolate, stirred it until it was all melted, took it off the water, did my dipping/drizzling, put them on parchment paper (or waxed paper), and if the chocolate got too thick or started to harden up again, back over the boiling water. Works fine for me *shrugs* Just make sure to not get any/too much excess moisture in the chocolate (I read somewhere that's bad lol.)

I've also read that dark chocolate doesn't need as much stirring as milk or white chocolate during melting, but I'm not sure how that works, I just stir mine until the lumps are gone - it gives me the impression it melts faster lol