here is what i did to phonon support under a linux environment:

first you need to compile gstreamer, in order to compile gstreamer you need the liboil library

the files I downloaded:
- liboil
- gstreamer
- gstreamer-plugins-base
- gstreamer-plugins-good
- gstreamer-ffmpeg
- qt 4.4.x for linux

1.
compile & install liboil

2.
compile & install gstreamer
configuration example to compile gstreamer:

PKG_CONFIG_PATH=/home/bin/qt/liboil/lib/pkgconfig/:/home/bin/qt/gstreamer/lib/pkgconfig/ ./configure --prefix=/home/bin/qt/gstreamer/

add gstreamer to your .bashrc

3.
compile & install qt
configuration example to compile qt with phonon support:
./configure -platform linux-g++-32 -prefix /home/bin/qt/qt44/ -qt-gif -qt-sql-sqlite -phonon -I /home/bin/qt/gstreamer/include/gstreamer-0.10/ -L /home/bin/qt/gstreamer/lib/

add qt to your .bashrc

this is how I compiled it without any problems to have phonon support....
hope it helps a little

greetz