In my most recent issue of the MacWorld Weekly e-mail newsletter, they reposted a hint that I hadn't yet seen on Mac OS X Hints. So this is a repost of a repost. :-)
They reported that on the Laptop Batteries special report on MacInTouch, reader Rob Wyatt reported that after trying and failing in everything he could to resuscitate his dead battery (reseating the battery, zapping the PRAM, resetting the Power Manager), he finally found a magic bullet. He booted the iBook into Open Firmware by pressing Cmd-Opt-O-F at startup. He then typed reset-nvram, hit the Return key, and then typed reset-all.
When his laptop restarted, the "battery was recognized and recognized and recharged perfectly. Subsequent readers confirmed that the technique revived batteries they too had given up for dead."
Mac OS X Hints
http://hints.macworld.com/article.php?story=2003071622115360