populating field A with content of field B I have a content type with several fields, e.g. phone1 and phone2. 

I would like to populate another type of field, "table_field", with values from the first two automatically, on creation of an instance of this content type. 

What would be the best way? Can I utilize tokens to do this? Thanks for your time, I appreciate it. This is my first project. Huge learning curve, and am enjoying it.
In Drupal 6 you could use Computed Field for that, but unfortunately it's not completely ready for Drupal 7 yet.

You could also create a custom module in which you implement hook_node_presave to set the value of 'field A' based on the value of 'field B'. When you choose this method, you may also want to implement hook_form_alter to hide field A from the node form.