GarageBand 2: THE TIME DISPLAY DOES MORE THAN SHOW TIME

If you're just looking at the Time Display, you're only seeing a tiny bit of what it does. For example, click on the Tempo (it's in the far-right corner) and a pop-up slider appears where you can adjust the tempo. If you click-and-hold directly on the time readout, you can move the position of the Playhead by dragging left, right, up, or down (and the amount the Playhead moves depends on which readout you click-and-drag on). To see the length of your song in minutes and seconds (rather than measures), click on the musical note icon on the left side of the Time Display.