I've been debating jumping to Photoshop CS6 for awhile. I've had every version of PS since version 1 way back in the distant past and have really looking for someone to show me what the differences between CS5 and CS6 were in an easily understandable way.
To help solve my dilemma, I grabbed a copy of Learn Photoshop CS6 Quickstart edition for the iPad. It's a US $5.00 video tutorial with about 2 hours of videos covering Camera Raw, the new Content Aware tools, HDR, black and white conversions, and the new blur and lighting filters.
French landscape photographer Serge Ramelli is an engaging teacher, and I find I learn more from a video that reading a book. Ramelli keeps it simple, although sometimes he assumes a bit more knowledge than a new user might have. In addition to the videos, you can download the files used in the tutorials and try the techniques yourself.
I learned quite a bit in a short time, and the app answered my questions about whether or not I should upgrade (I should). While my new iPad screen has the very sharp Retina display, I found that I really wanted a larger presentation. Apple AirPlay to the rescue! The videos look great on my 46" LCD screen via the Apple TV.
Ramelli has other video tutorials, including learning HDR, Photoshop CS5, and basic landscape photography. There are also some free previews available to download and sample. I've looked at some of these videos, and they are consistently high value in terms of content but they don't get too technical. It's pretty easy to walk away with new techniques you might have never discovered.
All these Ramelli tutorials are universal apps, but I think the iPhone screen is just too small for worthwhile viewing. The CS6 Quickstart is a 333 MB download and requires iOS3 or greater.