Here are my notes on installing Debian 6.0 to the Guruplug Plus.

None of this is original or my own work, but I found that I needed to refer to several different sources of information to get the job done.

I hope this is helpful, but the usual disclaimers apply: don't blame me if this doesn't work, or if it destroys your device.

Here we are installing to a microSD disk. If you are using a USB stick, the usb address will be different in the boot_cmd line below.

Update to a recent u-boot using this reference:
http://www.cyrius.com/debian/kirkwood/sheevaplug/uboot-upgrade.html.

From USB, do something like this:
Marvell>> usb start
Marvell>> fatload usb 2:1 0x0800000 uboot.bin
Marvell>> nand erase 0x0 0xa0000
Marvell>> nand write 0x0800000 0x0 0xa0000
Marvell>> reset

Or if you have no u-boot (you're in a bricked state), see the section "Flashing U-Boot on Bricked Plug" here:
http://plugcomputer.org/plugwiki/index.php/Reflashing_images_on_the_GuruPlug.

Main reference for installation, but note that some things are different here, because this page refers to SheevaPlug:
http://www.cyrius.com/debian/kirkwood/sheevaplug/install.html.

The Debian unstable installer for Guruplug is available here:
ftp://ftp.debian.org/debian/dists/testing/main/installer-armel/current/images/kirkwood/netboot/marvell/guruplug/.

Copy the uImage and uInitrd from that location to a DOS formatted USB stick.

Connect to the Guruplug with:
# screen /dev/ttyUSB0 115200

Then:
Marvell>> usb start
Marvell>> fatload usb 2:1 0x00800000 /uImage
reading /uImage
1434220 bytes read
Marvell>> fatload usb 2:1 0x01100000 /uInitrd
reading /uInitrd
3172851 bytes read
Marvell>> setenv bootargs console=ttyS0,115200n8 base-installer/initramfs-tools/driver-policy=most
Marvell>> bootm 0x00800000 0x01100000

The installer boots, and you go through the installation.

Then:
Marvell>> setenv bootargs_console console=ttyS0,115200
Marvell>> setenv bootcmd_usb 'usb start; ext2load usb 1:1 0x00800000 /uImage; ext2load usb 1:1 0x01100000 /uInitrd'
Marvell>> setenv bootcmd 'setenv bootargs $(bootargs_console); run bootcmd_usb; bootm 0x00800000 0x01100000'
Marvell>> saveenv
Saving Environment to NAND...
Erasing Nand...
Erasing at 0x60000 -- 100% complete.
Writing to Nand... done
Marvell>> boot

Now install emacs, isc-dhcp-server, linux-source-2.6.32, module-assistant, rsync, etc...

Create a suitable /etc/dhcp/dhcpd.conf.

Edit /etc/default/isc-dhcp-server to include the right interfaces (eth1 and uap0).

Now we need to get the wireless working.

Reference: http://lists.debian.org/debian-arm/2010/05/msg00081.html.

Now:
module-assistant prepare

(This command installs the necessary tools and headers).

Download the necessary source from:
http://lair.fifthhorseman.net/~dkg/machines/moo/libertas_uap.tgz.

Then:
mkdir /root/build-uap

Copy libertas_uap.tgz to /root/build-uap.

Unpack it.

In /root/build-uap/libertas_uap:
make CONFIG_LIBERTAS_UAP=m -C /lib/modules/$(uname -r)/build M=$(pwd)
mkdir /lib/modules/$(uname -r)/kernel/drivers/net/wireless/libertas_uap
cp uap8xxx.ko /lib/modules/$(uname -r)/kernel/drivers/net/wireless/libertas_uap

Get the firmware blobs helper_sd.bin and sd8688_ap.bin from the original image:
http://www.newit.co.uk/files-guruplug/guruplug-rootfs/.

mkdir -p /lib/firmware/mrvl/

Copy the firmware blobs to /lib/firmware/mrvl/.

Create a file /etc/modprobe.d/libertas_uap.conf:
# blacklist competing modules for the same hardware
# used by libertas_uap (uap8xxx.ko)
blacklist libertas_sdio
blacklist libertas

Now reboot.

Now sort out IP addresses for eth1 and uap0.

Add them to /etc/network/interfaces.

For example - add these lines:
auto eth1
iface eth1 inet static
  address 192.168.10.254
  netmask 255.255.255.0
  broadcast 192.168.10.255
#
auto uap0
iface uap0 inet static
  address 192.168.9.254
  netmask 255.255.255.0
  broadcast 192.168.9.255

Now we need /usr/bin/uaputl from an original Guruplug install, again from:
http://www.newit.co.uk/files-guruplug/guruplug-rootfs/.

Then we need a script to start the access point. Here's a very simple one:

#! /bin/bash
/usr/bin/uaputl bss_stop
/usr/bin/uaputl sys_cfg_ssid bellman
/usr/bin/uaputl sys_cfg_protocol 32
/usr/bin/uaputl sys_cfg_wpa_passphrase "mypassowrd"
/usr/bin/uaputl sys_cfg_cipher 8 8
/usr/bin/uaputl bss_start
/etc/init.d/isc-dhcp-server restart
iptables -F
modprobe ip_tables
modprobe iptable_filter
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

For accessing the internal storage if you want to do that later:
apt-get install mtd-utils

Reference:
http://www.plugcomputer.org/plugwiki/index.php/Installing_Debian_To_Flash.

Then you can do something like:
ubiformat /dev/mtd2 -s 512
ubiattach /dev/ubi_ctrl -m 2
ubimkvol /dev/ubi0 -N internal -m
mount -t ubifs ubi0:internal /mnt

Have a lot of fun... (although it's not openSUSE...)