I've successfully upgraded to Ubuntu 9.04 (Jaunty Jackalope).
What I learned:
The Dell install is proprietary. Upgrades are not supported by Dell, whcih
seems short-sighted to me, but I think they're trying to avoid support
calls.
In any case, it's fairly simple-back up any files first.
See here:
https://help.ubuntu.com/community/Installation/FromImgFiles
Download the Netbook Remix package:
https://help.ubuntu.com/community/Installation/FromImgFiles
Follow the usb image writer install and usage instructions and you'll have
9.04 in 20 or so minutes.
I'm still exploring it, but I have a lot more free space and everything
works.

                         PCBUILD's List Owners:
                      Bob Wright<[log in to unmask]>
                        Mark Rode<[log in to unmask]>