Put your chicken fresh or frozen into a crock pot.
Cover with Water (or Water and Chicken Stock, or Water and Veg. stock.)
Cook 6 hours on High or 8 hours on Low
The chicken will be so moist!! And, with the addition of Stock, nicely seasoned and yummy.
If you need your chicken done much faster you can boil on the stove for about 20 min for Chicken Tenders and longer (check for doneness) for full or half breasts.
My girls would not eat the Enchiladas I made the other night using this method, so I just pulled out 4 of the chicken Tenders (I use those most!) and put them on plates for the girls with some rice, and they had their dinner without me having to make an entirely separate meal for them!
I really prefer these methods over Microwave or baking when using Chicken in something else just to avoid the hard spots and dryness.