EDIT! Totally rewritten after discovered my tar.gz was corrupted. Apologies to all for misleading information
----
OK, so, after backing up my old angstrom install (which took a while as it was behaving oddly), I downloaded the zubuntu install file, and use the android install tools.
Notes
1/ I had to rename the .tar.gz to android-root.tar.gz and not android-rootfs.tar.gz as specified.
2/ when it says "reformat hard drive" it also wipes all partitions and creates one big one, so if you did have a separate /home, make sure you back it up
3/ you'll need quite a big SD or CF card to store the install files, they're quite big! It will also take quite a long time to unpack.
Good things
1/ my wired CF ethernet worked easily - had to set static IP because dhclient fails with "Can't create addrlist socket".
2/ my prism2 (zonet mercury zcf1100) CF card is detected
3/ usb keyboard worked fine
Problems
1/ pccardctl or cardctl is missing --edit-- FIXED! installed pcmciautils package
2/ the kernel has orinoco/hermes drivers, these are useless, you'll want hostap, so create /etc/modprobe.d/blacklist-hostap file containing lines:
blacklist orinoco_plx
blacklist orinoco_cs
blacklist orinoco_pci
blacklist hermes
Paul