IconBeast Lite is a high-quality and free iPhone icons set that iOS developers will probably like so much.

It is the smaller version of IconBeast Pro (that has 1700 items) but still has lots of icons (300).

There are items from actions to arrows, charts, devices, social networks and more.

They are in PNG format, sized 30*30px and free yet require attribution when used.

If you liked the quality of the set and still need more icons, make sure to check out IconBeast Pro | 1700 iPhone icons.

We all know the iOS folder interface: “clicking a folder changing the opacity of other elements and displaying the contents inside a sliding element”.

App-Folders is a jQuery that mimics that behavior and works on both desktop + mobile browsers.

Folders can include any HTML element (images, text, video ,etc.) and each folder gets its own URL that makes direct-linking possible.

The look/feel doesn’t have to be iOS-like but it can be themed completely for creating attractive layouts (check demo).

Mobile_Detect is an open source PHP class for detecting mobile devices.

It uses the User-Agent string combined with various HTTP headers in order to detect the mobile environment.

The class can easily understand whether the platform is mobile, tablet or desktop.

Also, functions exist for detecting whether it is iPad, iPhone, Android, Blackberry, etc.

And, we can even drill-down to the versions of the platforms and browsers if needed.

It has a huge library of devices (including Nook, Nexus, Kindle, Archos..) and browsers for a stable detection.

Makeappicon is a free and web-based tool for generating app icons quickly.

It works by simply uploading a big-sized image and the app auto-resizes it to the required dimensions.

The sizes are the ones that are required by iOS + Android apps.

Makeappicon accepts .JPG, .PNG and .PSD files (works best with a 1024*1024px image).

Ratchet is an open source toolkit for easily prototyping iPhone apps using web technologies (HTML, CSS and JavaScript).

It has lots of iOS-looking components like buttons, forms, bars, lists, toggles, sliders, etc. that can be inserted to the prototypes with few lines of code.

The download package is just the template files and the components library. Creating layouts is very easy and their look can be customized with CSS.

Ratchet is very well-documented and has lots of new features to arrive in the future.

NimbusKit is an open source iOS framework, mostly for experienced developers, that consists of various components.

The components are all modular, well-documented and aim to fill frequently-used but missing features.

Some of the components are: rich text label with hyperlinks, web view controller; an approach to table models, radio groups, table actions and more.

NimbusKit is developed + contributed by an active community and releases new features/updates frequently.

ViniSketch Designer  is a free software for visually creating mobile applications using web and native technologies.

It only works with Mac OS X and provides visual editors for designing the GUI + dataflow besides a code editor to customize the stuff in detail.

There is a built-in simulator and debugger which is based on the WebKit's WebInspector.

The apps created are compatible with iOS + Android and other platforms are under development.

Also, if you will be using PhoneGap for the app created, it can generate the project automatically.

Mobello is an open source JavaScript UI framework that simplifies developing mobile web apps.

The framework aims to provide a native-like experience in mobile, it is optimized for touch events and has 20+ widely-used UI components.

It also has an IDE, named Mobello Studio, that focuses on building mobile apps with HTML5, CS3 and the Mobello framework..

Mobello Studio has a drag 'n' drop enabled  visual design editor, a JavaScript debugger and built-in mobile device emulator.

The API of the framework is documented in detail and it can be a good alternative to other popular ones if improved regularly.

When it comes to tracking websites, there are open source analytics apps like Piwik, OWA or ChiliStats. But, for mobile, it is hard to find a good one.

Countly is a modern, real-time and open source mobile analytics application which can collect data from mobile phones and visualize that info for analyzing mobile app usage + end-user behaviour.

It is formed of 3 parts: the Countly server + frontend, iOS SDK and Android SDK.

With an event-driven system, almost every action can be tracked including in-app purchases, when a user closes the app, ad-click behavior, etc.

All these details are displayed in the slick interface of Countly. And, you are not limited to racking a single app. The same interface enables adding any number of apps.

Moobile is an exciting and fresh project; a mobile web application framework built on MooTools.

Currently, it is focused on providing a iOS-like experience on WebKit browsers and comes with many controls like bar, button, image, list, activity indicator, slider and more.

It also has support for transitions like fade, slide, cubic or cover and can display native-like alerts.

Interfaces created with Moobile are fluid, they will work well both in iPhone + iPad and look good when orientation changes.

The download package includes a boilerplate for quickly starting projects, related PSD files and a simulator.