This is where I am keeping iOS related things.. iOS has a sweetspot for me because it is the first thing I tried working on. When the iPhone 3GS came out one of the main features was a revamped camera, this new camera application had a feature named "Tap to focus". Pretty standard in modern smartphones, this was Apples first implementation of it.. they released it to my surprise (actually it was just a big let down) as a 3GS exclusive feature. Now as far as I knew the actual focussing part is when the camera is physically readjusting the lense so that is obviously physical hardware, but Apple also included some software that would adjust the lighting to maximize the light of what was being focused on in picture. I was a bored sophomore in High School and I wanted that feature immdiately. I found that by adjusting one of the core permission's in my phones filesystem I could get the software behind tap to focus to work correctly... I was apart of a few blogs at the time and I wanted to share what I had found.
I had found a clever way of packaging this application so that anyone could use it. Not everyone is comfortable messing with the permissions on their phone in the jailbreak community, so I packaged the tweak as a theme. Jay Freeman (AKA Saurik) made a VERY powerful theme engine that would not only override images in applications, I found it overrided anything in an application. Apple stores it's permission file in a odd location. "/System/Library/Springboard.app" (Other system applications are stored in "/applications" and "var/mobile/applications")
So packaging it as a theme and then using the application "Winterboard" (Sauriks theme engine) you could override the default permission file safely. If something went wrong on the phone, (saurik) made a something called "safe mode".. this would turn off all jailbreak addons, including Winterboard.. so if something had gone wrong, the would phone restart - Where all "Mobile Substrate Addons" are switched off - This also turned off the modded permissions file making it extremely safe use.
I then released the application for free thinking only ~50 people would use it. To my surprise around 28,000 downloads later it was my first successful release and to this day my favorite.
Download stats are the link below.
http://planetiphones.thebigboss.org/repository/pistats.php?file=iPhone%203G%20Auto%20Focus