I’m sure that there's a lot of blogs, tutorials, and presentations out in the public already, which educate us about the Fields API. I’m not going to write “another blog post” about that. Instead, I'm going to share my initial impression as well as what I’ve discovered helpful to people who are new to the API.

The behavior of Drupal cck's single on/off checkbox field is a little different than other cck fields. Normally, a field has a label above its input element (text field, select list, ...). With a single on/off checkbox the field label as entered when creating the field does not appear on the node edit form. Instead, the label associated with the 'ON' value will appear to the right of the checkbox. This is the intended behavior and when the label associated with the 'ON' value is descriptive, it is intuitive enough on the node edit form.