Desktop application: C++, VC++, MFC, QT,C#, VB.NetMac Desktop Applications: Objective C, cocoa framework, shell scripting , Apple scriptingMobile apps: iPhone,iPad, Android , windows mobileWeb Development - PHP, JQuery, Prototype, Zend, jquery, javascript, html5 Ajax & Web-ServicesServer & Toolkits: OpenFire, XMPP library (all platforms), chatting client (all platforms) Deployment & installers : Inno script based installer, wix scripting, NSIS, installShield, package maker (Mac)