I find melting chocolate in the microwave very effective, providing the microwave temperature is set at medium, not high, or you'll have only-suitable-for-spearmint's-revenge. Give it 30 second bursts, stirring each time, it'll take about two minutes. I stir with a wooden skewer, as none is transferred to the spoons (for it to harden and me to lick off thus reducing the proportion I need for the recipe :P )
I find this a lot easier than the doulbe boiler method, as you have to be so careful not to let any moisture come in contact with the chocolate.