xbattbar 1.4.2-5.1 (sparc binary) in ubuntu intrepid

 Xbattbar displays the current (laptop) battery status in the X window
 environment. Battery status is obtained through the APM interface.
 .
 The battery indicator of this program is very simple: a simple bar
 at the top/bottom of your display. With its color, it indicates the
 AC-line status (plugged in or off-line), and battery charging/remaining
 level. Also, if the mouse cursor enters the indicator window, a popup
 diagnosis window comes up in the center of your display showing the
 current AC line status and battery level.
 .
 If you use ACPI take a look at xbattbar-acpi.