GarageBand '11: beat ruler
The beat ruler runs horizontally across the top of the timeline. It shows the divisions of time in either beats and measures or minutes and seconds, depending on whether you choose Time or Measures in the LCD.
When you move the playhead or a region in the timeline, you can use the beat ruler to place it at the correct point in time. While the project is playing, you can see what part of the project is currently playing by watching the playhead move across the timeline.
When the timeline grid is turned on, the units shown in the beat ruler reflect the value set in the timeline grid.
If you turn on alignment guides, you can use the alignment guides with the beat ruler to make sure regions and other items are aligned with beats, measures, or other units of time.