Is there an iPhone equivalent to the NSTokenField control?

In my app I want the user to type names into a UITextField (or equivalent) and then when they press return, it will put that word(s) in a blue bubble that's usually associated with tags. The cursor then moves to the end where they can add more "tags". This can be seen when adding contacts in the To, CC & BCC fields in the Mail app, and also when selecting contacts in the Messages app. How is this done? Is it something that's provided in the UIKit or available somewhere else? Many thanks, Michael