If you’re switching between providers and want to keep your addressbook and sms’s, here is a simple way of doing so with gnokii:
$ gnokii --getsms AR 1 10 -d >> sms_archive $ gnokii --getphonebook SM 1 200 > phonebook
The “AR” stands for “ARchive” and tells gnokii to search the SMS’s there, and not in the INbox (“IN” being another cellphone storage area). Following AR, there is the SMS range you want to save (sms 1st till 10th). Make sure you have a look at gnokii manpage if this is not working for you. For instance, on the following command, the “SM” is referring to the SIM card… perhaps you’re not storing your phonebook there, but in the internal mobile phone memory (“ME”).
As a result of this mini-howto, you have a plaintext copy of your phonebook and sms messages on your computer, isn’t it easy and convenient ? :) Sure, there are clearly better and comprehensive alternatives out there, like SyncML (OpenSync), but this solution suits my needs very quickly and it’s quite effortless.