plotting - Display function value on hover?

I have used Manipulate in conjunction with Plot to draw a function's graph and I would like to show the current x-axis value and function value while hovering over the function's plot. How can I achieve this?

Thanks.

Answer

Manipulate[
 Module[{tbl},
  tbl = Table[Tooltip[{x, Sin[a x]}], {x, -Pi, Pi, .1}];

  ListLinePlot[tbl, Mesh -> All, MeshStyle -> Opacity[0]]
  ],
 {{a, 1, "a?"}, .1, 5, .1}
 ]