are there prebuilt qt-binaries or does one always have to build it himself?

[gfunk]

Yes, Trolltech distributes installers that will install both pre-built binaries and source. From there, you can further configure your Qt install for other platforms.
It's in here:
http://trolltech.com/developer/downloads/qt/windows

Of course, if you need VS2005 support, you have to buy the commercial version of Qt. Otherwise, MinGW is your c++ compiler.

[darksaga]

Of course, if you need VS2005 support, you have to buy the commercial version of Qt. Otherwise, MinGW is your c++ compiler.

You can use VS2003, VS2005 & other versions with the open source edition, without a problem.

But then you have to build your binaries, and apply some patches, e.g. for VS2003 you can find the patch here.

How to build your own version you can read here

it takes some time, but is not a big deal...

greetz