Take a look at the "Demo.Advanced" code (either in the Demos.Metro, Demos.SL, or Demos.WP7 subfolder) int the download.
It defines two sounds:
_soundAddItem = new SoundMain(cnvGame, "Assets/sounds/trampoline.wav", 3, 0);
_soundHit = new SoundMain(cnvGame, "Assets/sounds/hit.wav", 5, 0);
... and then plays those sounds in the Collision event and when items are added...
void cnvGame_Collision(PhysicsSprite sprite1, PhysicsSprite sprite2, FarseerPhysics.Dynamics.Contacts.Contact contact)
// this event is fired for each sprite to sprite collision
// taking into account CollisionGroup.
if (PhysicsUtilities.GetMaxCollisionForce(contact) > 0.3)
You can use this technique, but you would wire up the "Tapped" (or "Tap" for WP7) event for the PhysicsSprite to play the sound.