I succeeded (one way) in syncing my Sony Ericsson K800i using the OpenSync Ubuntu packages: as stated on their website, they are in a very early stage of development!
You could find the following notes useful.
add
deb http://www.in.fh-merseburg.de/~jahn/opensync-0.21/ feisty main
to your
/etc/apt/sources.list
install
libmultisync-plugin-backup
libmultisync-plugin-evolution
libmultisync-plugin-irmc
libmultisync-plugin-irmc-bluetooth
libopensync-plugin-evolution2
libopensync-plugin-evolution2-dev
libopensync-plugin-file
libopensync-plugin-gnokii
libopensync-plugin-google-calendar
libopensync-plugin-gpe
libopensync-plugin-irmc
libopensync-plugin-jescs
libopensync-plugin-kdepim
libopensync-plugin-ldap
libopensync-plugin-moto
libopensync-plugin-opie
libopensync-plugin-palm
libopensync-plugin-python
libopensync-plugin-sunbird
libopensync-plugin-synce
libopensync-plugin-syncml
libopensync0
libpisync0
librsync1
libsynce0
libsyncml0
msynctool
multisync
multisync-gui
opensyncutils
python-opensync
using multisync-gui, set the syncml-obex-client plugin for the source with
<bluetooth_address>xx:xx:xx:xx:xx:xx</bluetooth_address>
<!– your sync ml channel –>
<bluetooth_channel>1</bluetooth_channel>
<identifier>PC Suite</identifier>
<version>1</version>
<type>2</type>
and set [...]
