Drupal 7 and Fields in Core
Most of CCK has moved to core in the Drupal 7 version. The D7 version of CCK contains nodereference and userreference (mostly working), fieldgroup (not working yet), data migration code (partially working), and some miscellaneous helpers to do things that core will not do, like maintain the php code snippets some fields may have been using to define allowed values (partially working). The future of Content Copy and Content Permissions has not been decided and nothing has been done with them. Everything else is in core.
CCK Resources
CCK is a very powerful system with many different contributed modules to extend its functionality. Install the Advanced Help module for additional help, and use the Views module to display CCK information in a variety of ways.
Here are a few other comprehensive documentation and tutorial resources to help get you started:
* Text: The CCK Handbook on Drupal.org
* Text: CCK Module basics tutorial
* Video: Adding Fields With CCK video
* Video: CCK & Views Tutorial (for Drupal 5)
* DVD: Learning CCK in-depth training by Lullabot
* Book: Using Drupal O'Reilly covers CCK with lots of examples
* Video: Karen Stevenson's CCK Presentation at the Do It With Drupal Seminar (paid access)Read more