Just curious, did I overlook somewhere in the API to display a chat bubble type image as found in the iPhone's SMS application? There's a few applications out there that use bubbles that look verbatim to the iPhone's and I'm wondering if they're using a native widget or their own image.
This is also seen in the Tweetie application where the content of the tweets are.
You need to use your own images, and Apple recommends using 9 UIImageViews (3 rows of 3) (Top Left Corner, Top Middle, Top Right Corner, Middle Left Side, Middle, Middle Right Side, Bottom Left Corner, Bottom Middle, Bottom Right Corner)
Read the code in UICatalog's ButtonsViewController.m: "+buttonWithTitle:" which creates a stretchable button from one image, which is the same case for creating a chat bubble.
I stumbled across this today from one of my RSS feeds.
Its a bunch of UI elements re-created in illustrator
Notably they have the chat bubbles. You might be able to use them as a start for images to do what kdbdallas is saying.
http://www.mercuryintermedia.com/blog/index.php/2009/03/iphone-ui-vector-elements
Hope this helps.
chris.
I suggest using the stretch method they recommend for button images.
[UIImage stretchableImageWithLeftCapWidth:15 topCapHeight:13]
You can see a working example by downloading Twitterfon's source(it's on the FAQ page). You can see how they code a reusable control for it as well as example images for creating your own bubble.
Edit - Source is no longer available(NDA, possibly)
I put the image up here. You should be able to figure out the rest :)
There is a video tutorial showing Jabs method here http://vimeo.com/8718829 it includes bubble graphics in many colours. Also the the twitterfon source is here http://github.com/jpick/twitterfon.
(these should be comments to jabs answer but I don't have high enough rating to comment)