How can I supply the compiler with paths to the include files and libraries?

I am new to Qt and I can't include the Qapplication header. I am using Xcode on mac osx, and MS visual C++ 2005 on windows xp.

How can I supply the compiler with paths to the include files and libraries?
Can't speak for M$ products because I'm such an M$ hater but I would say read the documentation and help files about including files. Xcode uses the GCC compiler which I am familiar with. From the command line you use -I %26lt;path%26gt; and -L %26lt;path%26gt;. If you are using an IDE you can compile from then you'll just have to read the documentation about projects in that.