Registration full name I would like to edit the registration fields, but I can't find where to do it.
I want to replace the username field on the registration form with two fields for first name and last name, which are then used to create the username as &lt;first name&gt; &lt;last name&gt;.
There is Auto Username for Drupal 6, and there is a Drupal 7 port of the module sitting in the issue queue.
Perhaps you could test the zip that is attached to that ticket, and help fixing any bugs. ;)

Alternatively, perhaps you could make this happen using the Rules module.