Recently I did a review for FixYourGame.com in which I touted the benefits of filming your swing and having it reviewed by a PGA professional. I still stand by that idea, but I also think there is a lot of value in filming your swing for your own instant review. In the past I have used an iPhone for this purpose, simply propping the phone up on my bag and filming a few swings. Unfortunately, the playback on the iPhone will not allow me to go frame by frame, which is critical for spotting problem areas like an early release (hypothetical of course). As a result, I just cannot see what I am looking for with the standard playback on the iPhone because it skips over too many frames. The work-around for me was to download the video to my computer and watch the raw .mov file, where I could click through the video frame by frame. This process works okay but still does not solve the instant analysis problem.
Now with the Hank Haney iPhone app you have the ability to instantly review your swing in stop motion (or close to it). So while everyone at the range thinks you are texting your supermodel girlfriend in between swings, in reality you are nerding out over your sweet, sweet clubhead lag, inch by awesome inch.
While this is the part of the app I use the most, there are two other tools that come with the free app: the ability to take a snapshot of your swing and the capability to draw lines on the screen (angles and such). Both of these tools are fairly handy, but ultimately for me it is just a great way to capture swings, store them, and check to see if you are making progress on a certain issue. This of course assumes you know what you are looking for, which is probably a big leap of faith.
While the app is free, Hank does offer a service to have your video reviewed by his staff (I think it is like $25.00 per lesson). Since I just had a video review from FixYourGame.com I have not gone though that process, so I cannot speak to its value.
With that said, the free part of this app is the best method I have found for simple, free and instant video review.