Melting chocolate in the microwave, a cooking technique by cookshow.com. How to Melting chocolate in the microwave. :

Place chocolate (and shortening if you're making candy coating) in a small, deep microwavable bowl. Use a 50% power setting. Nuke in 30 second intervals, stirring between each interval. The chocolate will keep its shape even when melted, so stirring is important. Reduce nuke time to 10 seconds if you suspect chocolate is close to being melted. Alternatively, just let it sit for a minute or two to complete the melting process.