2.6.33.4 is now available.
This version should support the GuruPlug. I haven't heard back from anyone trying 2.6.33.3 with a GuruPlug.
Kernel and modules are available from the following location:
http://sheeva.with-linux.com/sheeva/Features sata, dmcrypt, IPV6, CIFS, NFS4, EXT3, EXT4, JFS, XFS, FUSE(for ntfs-3g), UBIFS, usb-serial, uvcvideo, iptables, appletalk, bluetooth, v4l and ppp.