If you are looking to programatically create nodes, use the Drupal API.
Start by creating a $node object. Fill in title, type, status, body, plus any CCK fields. At the end, call node_save($node);.
node_save will save your node object and do the necessary database work.
Check this out:
http://api.drupal.org/api/function/node_save/6
http://mediumexposure.com/how-build-node-drupal-programmatically/
The easiest way to see what each type of content type has as fields is to create a node (for example, Page), then use var_dump() to see the node's contents. That will show you every field you will need to use in your node object creation script.
Some folks will say you should create a form array, and call drupal_execute() on it so validation is performed before it's saved to the database. Either way is fine.