I have successfully synched my contacts in Evolution on Ubuntu Hardy on my laptop with GPE contacts on the Nokia N810 using multisync with evo2-sync and gpe-sync plugins.

This link gave me the inspiration:
http://www.cleardefinition.com/page/...d_GPE_on_N800/

As I could not install the package libopensync-plugin-gpe with normal apt-get or synaptic, I downloaded the debian package here:
http://packages.debian.org/de/lenny/...n-gpe/download
or you add
deb http://ftp.de.debian.org/debian lenny main
as mirror server as stated.

I started struggling with setting a password for the standard user account "user" on the tablet. When typing passwd user in xterminal, I got the message that changing the password of user is not possible. So I used my root account (has been created when installing xterminal as I have been prompted for specifying root password) to synch my contact data. Therefore you have to specify "root" in the settings of gpe-sync plugin in the field "handheld_user". Executing the synchronization, you will be prompted for your root password. Then the contact data from Evolution on the computer won't be synched against /home/user/.gpe/contacts on the tablet as expected, but against .gpe/contacts in the root folder! You just need to add a softlink to the original location with
ln -s /home/user/.gpe/contacts contacts (being in /.gpe in root directory of the tablet)
so the requests are redirected to the contacts in the user directory that is used by GPE-contacts itself.
Might also work for calendars and todos, but I haven't tried yet.

Summary (what you need):
on the computer:
Evolution (if not shipped with distribution already)
multisync
plugings evo2-sync and gpe-sync
ssh (for creating the softlinks on the tablet)

on the tablet:
gpe-contacts (gpe-calendar, gpe-todo...)
gpesync