resizing UITextField?

Hi, is there a way to dynamically size a UITextField as the user is entering text? I would like the textField to start out at a default size and then grow as long as needed to accomodate the entry, perhaps with a maximum size and line wrapping.

Ideally, if this is possible, I'd like to know where this can be set in IB, but a programmatic solution will work too.

Also, is there an easy way to dismiss the keyboard?

thanks,
Cliff