Content type fields and user account
I have made a custom content type (named "personal info") that contains several fields; one of them is "surename". And I have set that content type to be part of registration page, so that user has to fill fields from the content type "personal info" together with the basic drupal fields (username, email, password...) to complete the registration process.
Now I have 2 questions:
1. I used function hook_form_alter (in a custom module named "jobnetwork") to change some data from the content type on the edit user page (user/x/edit), where I can and I succeeded in changing label of the field "surename" (I used $form['field_surename'][0]['#title'] = t('some text');), but I could not disable the field (I used $form['field_surename'][0]['#disabled] = true;, $form['field_surename'][0]['value']['#disabled] = true; and other variations but had no success). How can I disable that field?
2. I want to change the way the drupal stores data from my content type "personal info" into the database (actually I want to do some checking and altering of the data that I collect from content type fields on registration page) and I tried to search trough the user_register_submit() and user_save() functions in user.module , but had no luck. Can anyone tell me where can I do this?

can node profile and node
can node profile and node family, user profile kind of module can help you ?
I'm using Drupal 6, and have
I'm using Drupal 6, and have install autoassign role module and content profile module. Those modules that you are suggesting are for drupal 5 and I can't use them.
2. have you try from user
2. have you try from user validate hook?
For 1st question, I couldn't
For 1st question, I couldn't find any solution as much as I tried. It looks to me , like there is some sort of bug. Cause all other fields that don't belong to content type (that I use like content profile), I can change (rename title, disabled,....)
Anyway, I enabled Content Permission in CCK module, and set permission so that anonymous users can edit it (when they sign up for the first time), and authenticated users can only view it. So this works ok for me. Not exactly what i wanted, but it is a good replacement.