it is rooted since some time already.
files and instructions are in the following archive, but since instructions are in korean, i'll do a writeup below.
(argh! spambot won't allow this link, so you'll have to piece it together...)
edit: needed files are also in an attachment below
the gist is that you need to flash the boot partition via fastboot, setup root and busybox, and then modify secure->install_non_market_apps in settings.db.
you will need to have adb and fastboot from the android sdk working on your computer. There are many posts about this elsewhere, so i won't go into the details.
also, i only print filename without path, just find the corresponding file in the mentioned archive and modify the commands accordingly.
flash the boot partition via fastboot
first get your kyobo into fastboot mode (with usb cable attached) by pressing volume-down at bootup. timing here can be a bit finicky, but easiest seems to be to shut it down completely and then press just after pressing power.
issue a 'fastboot devices' on computer, if successful it should give you the response '???????????? fastboot' or similar. if empty or hangs, try again by rebooting the kyobo by pressing power with volume-up held (you can go into fastboot immediately after reboot by volume-down as expected).
when positive response above, you can flash by
fastboot flash boot boot.img
and then reboot by
simplified fastboot instructions, thanks to smb_gaiden, whose button-poking-fu is strong.
setup root and busybox
with boot partition flashed you now have adb access, so let's use it. let the device boot as normal, and then issue the following.
adb push busybox /data/local/tmp
adb push fixsu.sh /data/local/tmp
adb push su /data/local/tmp
adb shell chmod 777 /data/local/tmp/busybox
adb shell chmod 777 /data/local/tmp/fixsu.sh
adb shell chmod 777 /data/local/tmp/su
adb shell /data/local/tmp/fixsu.sh
adb shell ln -s /data/local/tmp/busybox /system/xbin/busybox
after this, install some apk's from the archive
fix non-market apps setting
adb install superuser.apk
adb install blackmart.apk
only thing left is to change a setting to allow non-market apps to be installed. if you don't care about your current settings (locale, etc), you can just push the settings.db from the archive like so:
adb push settings.db /data/data/com.android.providers.settings/databases/
if you *do* care about your settings, you'll need to pull the settings.db, edit it in some sqlite db editor (set secure->install_non_market_apps to 1) and push the result.
that's it. all rooted. now you just need to install angry birds and yer' set ;)