http://www.irextechnologies.com/supp...ry_replacement
More info here:
http://forum.irexnet.com/viewtopic.php?p=5153#5153
Coming in Q2 2007. Hopefully it will be user replaceable. Out of the box, it will bring the iLiad to 15 hours, but for those who want to underclock their CPU, I'd imagine we can get upwards of at least 20.