How do I do that? I can't find any tutorial describing this. Well, I've downloaded win7 64bit version of Qt 5, I installed this (more than 1gb, wow...). However, I still cannot include any Qt library.

#include <QApplication> displays - cannot open source blah blah blah.

What else should I do, am I missing something here?

Another thing is - won't this 1gb Qt thing slow down my application? I'm not writing any big projects, just simple algorithms, cpp files usually don't go more than 20kb.

And one more - what does nokia has to do with Qt? I've already seen a couple of times the nokia company name while I was reading something about the Qt.

What else should I do, am I missing something here?

Install qt vs addin v 1.2.x

Another thing is - won't this 1gb Qt thing slow down my application?

Nope. Why do you think, that data stored on your drive will slowdown your programs? Your music / video will not, same qt libraries.

Btw, Qt runtime is quiet small (about 4 mb for simple GUI applications).

what does nokia has to do with Qt?

Nokia bought Trolltech with qt for their mobile platforms. And now it sells qt to Digia.

Feel free to use google ;)