Ahm you may elaborate more on what you currently need, not enough info there. :spin:
You can reset your bones to the original state (rest pose you made in edit mode) by using Alt+R and Alt+G (You can reset scalling by using Alt+S), which will reset the rotations and positions on the bone, in the pose mode.
Snapping bones is just like snapping any other object, and the shortcut is Shift+Tab, and the snap mode Shift+Ctrl+Tab. The icon is a little magnet in the bottow of your view.
You can also select any object or element, press Shift+S, select Cursor to Selected, and that can move the 3D cursor to that point, now you can select the object you want to snap, Shift+S again and select Selection to Cursor. That is a useful tool that blender has.