I know that there were some changes in this filed with the
introduction of TQt with already translated Q* objects to QT*. But I
have I noticed on my system another thing having both qt3.3.8d and
qt4.8.0 installed and I don't know if there are movements to resolve
this.

Qt provides set of tools that enable creation of qt-based
applications. Those are: assistant, designer, linguist , lrelease,
lupdate, moc, qmake, qtconfig, uic. Those are provided both by qt4 and
our qt3.
If I have both of the qt versions installed and I try to run one of
those applications, only the qt4 versions are launched, and I am
unable to launch qt3 ones unless i specify full path to them as
command.
That may be because I installed qt4 as second, and if I were to
install it first and then qt3 then I'd be able to start only those
provided by qt3.
If I run those commands through whereis I get:

assistant: /usr/bin/assistant /opt/qt/bin/assistant
designer: /usr/bin/designer /opt/qt/bin/designer
linguist: /usr/bin/linguist /opt/qt/bin/linguist
lrelease: /usr/bin/lrelease /opt/qt/bin/lrelease
lupdate: /usr/bin/lupdate /opt/qt/bin/lupdate
moc: /usr/bin/moc /opt/qt/bin/moc
qmake: /usr/bin/qmake /opt/qt/bin/qmake
qtconfig: /usr/bin/qtconfig /opt/qt/bin/qtconfig

Obviously, if I invoke assistant, the first path is executed.

As a temporary solution for my packages I create links to the qt3
tools in $prefix/bin/ and name them in the Qt3* scheme. Anyway I think
those should be renamed in the TQt3 to avoid collisions with Qt4 ones.