@por, I haven't measured battery life yet. Only basic power management works for now (boot, reboot, shutdown).
You can install all programs from Ubuntu 10.04 repository, including xournal.
@Kirth, first partition can be any size, second should be at least 2G. There's no swap partition atm.
Also I recommend using class 10 SD card. In future, I'll include installer with option for installing Obuntu on internal memory.