like this one here:
http://i27.tinypic.com/1zw0tqc.jpg
Is there an existing class that I can use?
You can use some of the string drawing methods to find out how large a frame you need for each tag, and then size a bunch of UILabels to fit each word.
As you'll likely want your user to interact with the tags, subclass UILabel to handle touches where appropriate.
We have developed such a component at Surgeworks Mobile (http://surgeworksmobile.com). Please contact us if you still need it.