Qt is a cross-platform toolkit from Trolltech used for developing GUI applications for Windows, UNIX/X11, Mac and Linux Embedded. There are many others like GTK, Motif, TCL/TK. But, a little research on the net will show you why it’s the most preferred. Well I’m not some authority to comment on its more technical nitty gritties but the experience of the few months I’ve had with Qt is encouraging to say the least. It’s got a wonderful IDE, with widgets( control elements in Windows like Buttons, Forms ) with the drag and drop features( like Visual Studio in Windows ). Some of the well known applications created using Qt are Opera, Google Earth and Skype.
The event and event handlers concept which we are so familiar with in Visual Studio is known as signals and slots here. eg If a user clicks on the close button, we want the close() function to be called. A signal is emitted when a particular event occurs( button click here ) and a slot( event handler ) is a function that is called in response to a particular signal. If you have some experience in C++, learning Qt is absolute fun. It also comes loaded with numerous examples and a wonderful documentation that makes sure you never will have to refer any book while learning Qt. It is available under a dual license : a free evaluation version( under GPL ) and a commercial edition if you intend to use it for developing proprietary software
Well as of now, I’m using it on Linux for my final year project but it can also be used in Windows where it is integrated with Visual Studio. That’s the beauty of it. You can use it on a Windows platform for creating an application targeted for Linux or you can use it on Linux for an application targeted for a Mac. Still haven’t discovered even half of its features and I can’t wait to get going. 
P.S: Thanks Reddy!
