Setting WAKE ON TIME

Set an alarm for waking your pc at a specified hour
$sudo sh -c 'echo "YYYY-MM-DD HH:MM:SS" > /proc/acpi/alarm'

To wake everyday set the DD as 00 (zero zero),
for example:
$sudo sh -c 'echo "2007-10-00 08:50:00" > /proc/acpi/alarm'

To verify the wake up time use $cat /proc/acpi/alarm
and check your BIOS~properties an PC startup.

Source:
http://ubuntuforums.org/archive/index.php/t-349062.html
http://acpi.sourceforge.net/documentation/alarm.html