Ok, so it is just one tool so far.
Back in the day, when you didn't know what a font was, you just slogged through font books for hours. Then email helped us sub this little job out to our network of design friends.
Then, finally, someone got computers to do their job: make our lives easier. whatthefont.com enabled you to upload a graphic and get a pretty educated guess as to what font it actually was... with of course the hope that you would then purchase it from your AI font benefactors.
Well, now the internet is in your pocket, and the time when you are most likely to see a cool font you want to use is when you are no-where near a computer.
Ta Da: WhatTheFont for iPhone !
Snap a pic, upload it, get your answer, all from right where you are standing, whether it be in a bookstore or walking down the street.
My tests with it had mixed results. Basically, if your image is not black font on white background you are in trouble and need to clean things up back at the lab with Photoshop - just like the web app. I was however able to shoot some Blue Shield letterhead and get Avant Garde Medium returned as the result... Correct!