Hi,
I downloaded QTCreator (.bin file) and I followed the instructions to install it on my Fedora 10.
After that I found out that I already have QT3.3 installed - more precisely, it came with the Fedora 10 OS installation.

I created a project in qt creator but it is not building, and I get this error message:
No valid Qt version set. Set one in Tools/Options
Error while building project qt_test
When executing build step 'QMake'
Canceled build.

I found under /usr/lib qt-3.3 and qt4 folders. Does this mean I have both installed?

Can anyone suggest any solution(s) to what I need to do.

thanks

You certainly may have both and there is no problem with having both. To develop with QT you will need the devl package, I'd recommend that you develop using QT4. In Qt Creator look at Tools->Options... QT4 to add the path to the development libraries.

I tried adding the path, but I am not even sure what I need to point to.
When I opened Tools/Options there was a QT tab and I added the path /usr/lib/qt4 to it but I keep getting '/usr/lib/qt4 is not a valid qt directory'.

Is it possible that when I downloaded the bin file from qtsoftware.com it didn't contain the development package?

I have one more observation that might help....
I created a very basic project and in main.cpp, the generated code is:
#include <QtGui/QApplication> but it is underlined and the message says QtGui/QApplication: No such file or directory.

Where should I expect to find this QtGui/QApplication ?

I think that you need to to install the QT4 development packages, go to the system menu -> administration -> Add remove packages (or which ever package manager you use) and select QT toolkit (for fedora 10 this will be version 4.4.3)