Yacpi is an acpi monitoring program for Linux. It displays various acpi information like battery status and ac status on notebooks. The main reason why i wrote this program is, because i don't like the acpi program, which is included in debian :) It displays things like battery status, ac status, cpu frequency, remaining battery/charge time, temperature... It also supports the use of more than one battery and can display them.
This is a screenshot of version 3.0:
plain-text output: yacpi -p
| BAT0 = 86% discharging rtime 04:09 h | ac = off-line | THRM = 50 C | gov = ondemand | cpu = 600/1500 mhz