Question: anyone knows a jQuery plug-in for text zoom a-la MAC OS X "Large Type" function in Address Book? I'd use it for the same situation - to show full-screen phone number after clicking on it.

Cheers

Answer: 
I recently extracted a jQuery plugin out of an application I'm building that does exactly this. <http://zoomabletype.tatey.com/>
You can use jQuery [BlockUI plugin](http://malsup.com/jquery/block/) to create this kind of "Large Type" effect. Check samples and use custom css to show ph. numbers.