This is a simple script, that converts XML phonebook from Gammu (Nokia) to MyPhoneExplorer (Sony Ericsson) format. I needed it only once to transfer contacts from an old phone, maybe someone else finds it useful as well.
Export a XML phonebook from any Nokia phone with the app Gammu
Select it here for parsing and save the output
Import your new phonebook to Sony Ericsson phone with the app MyPhoneExplorer