I’ve designed a couple – what type of verification are you looking for? Are you looking for a verification of the type of phone the user has or a UI where the user enters a verification code they receive via a text message?
If it’s the former, then I like the UI on http://www.tracfone.com when you are activating a phone – you can filter by manufacturer and it’s a visual “picker” (you click the phone that looks like yours).
If it’s the latter, then you just have to show an example of how the message would look – I’ve done it where you show two UIs, one that displays a “candybar” phone text message the other where you show an iPhone-like “Push” notification. It helps novice users know what they need to look for.