I found this program that just installs very easily and gives you a thin battery strength bar across the top of the screen. The bar changes colors as the bayyery strength goes down.
I hated not having the time available when on the phone or in certain programs like reading programs.
After you install this, you can go to settings/all settings/ clock and alarms/ and check "display the clock on the title bar in all, programs". Best of both worlds.
The bar changes white and shows how much the battery is charged when plugged in. (All colors are adjustable in the configuration program as is bar width).
IMPORTANT: Do a soft reset after installation. I had one freeze up on re-boot, did a soft reset and it's worked perfectly ever since.
http://forum.xda-developers.com/showthread.php?t=640139