when installed phonelink looks for the phone you might have configured to use with the IT upon first boot. if it finds it it generates a valid gnokii config file.
if not you have to write it yourself : there is an example in http://garage.maemo.org/phonelink.
if you want phonelink to show your GPE contacts you have to install contactInfos !
it always helps to know your phone model (and no N800 is not a phone)