Check out the post of Basic Mic'ing Techniques for Piano from ChurchAudio.

I'm finding some worship team pianist's like to play a regular piano instead of an electric such as the Clavinova.  While a baby grand does have a great sound, toss in a guitar, some drums, and a whole congregation singing, then you see why you need to mic the piano.  JB shows in his article that it usually takes more than one microphone.