Rails 3: What is the proper way to respond to REST-ful actions with JSON in rails?

I'm trying to make an API for my rails application using JSON responses to RESTful resource controllers. This is a new experience for me, so I'm looking for some guidance and pointers. To start things off:

1. In a rails application, what is the "proper" way to respond with JSON to REST-ful controller methods? (create, update, destroy)
2. Is there an idiomatic way to indicate success/failure through a JSON response?

Additional information:

• I'm currently working with rails 3.0.beta2
• I would like to avoid using a plugin or gem to do the grunt work, my goal is to gain a better understanding of how to make a rails 3 API.
• Links to places I could find more information on the topic would also be appreciated, some quick searching on google didn't do me much good.