iPhone - what controls needed for a chat style app? (easy question)

In a portion of my app I need to make a chat between two users... I know how to send the messages between both but I don't know what are the best controls I have to use in the UI... I want a UI similar to WhatsApp(simple and very good looking)

For example:

_{(source: mzstatic.com)}

• At the bottom... maybe a UIToolBar + UITextField + 2x UIBarButtonItem?

• In the middle(the messages)... I really don't know, this is my biggest question, the bubbles.

• In the Top... maybe a UINavigationBar + 2x UIBarButtonItem?

I'm new making UIs but I'm sure that this is a easy question for you and this is the final step that I have to learn to finish my app =)

I don't want code, only the UIcontrols/hierarchy and/or any ideas if it's possible =)

Thanks in advance ;)

P.S: Sorry for my english :S