XNA 4 includes the Microsoft.Xna.Framework.Audio.Microphone class which can seemingly read the raw sound data off the microphone via its API as documented:
GetData - Gets the latest recorded data from the microphone.
GetSampleDuration - Returns the duration of audio playback based on the size of the buffer.
GetSampleSizeInBytes - Returns the size of the byte array required to hold the specified duration of audio for this microphone object.
Can I read sound data using this class, record it in an array and then play it back? On the Xbox 360?