Qt4 does not respect DESTDIR= for installing as a user, but it accepts INSTALL_ROOT= for the same purpose.
It is tempting to build it with -no-qt3support to cut down on the vast amount of things it installs, but that appears to be inadequate to build kdelibs-4.1.3.
*update 20100219: Made it to kdebase-4.4 before running into any errors about Qt3Support, turns out kdebase needs qt and kdelibs to be built with qt3support.
Tired of that pesky licensing prompt (probably only useful for scripting,) try: sed -i.orig 's/COMMERCIAL_USER=ask/COMMERCIAL_USER=no/g' configure and append -confirm-license to your configure line
For 4.8, add '-opensource' to the configure, you can now use 'yes | ./configure'
If you build in /usr, unlike the book, all sorts of "rubbish" gets scattered across $PREFIX. That doesn't matter in /opt, but for tidiness in /usr you can fix this by passing
-docdir /usr/share/qt4/doc -plugindir /usr/lib/qt4/plugins \ -importdir /usr/lib/qt4 \ -datadir /usr/share/qt4 \ -translationdir /usr/share/locale \ -sysconfdir /etc/qt4
For some reason, the .pc files point to the build directory, If you have deleted that, packages such as vlc and at least one of the gst-plugins will fail to build until the pc files have been fixed. I happen to build in /usr/src - if you build elsewhere such as /home, the sed needs to match the path currently in these pc files and change it to /usr/bin (if your prefix is /usr). You do this after the install, so you can review these files before backing them up and finding a sed that works for you.
sed -i 's%/src/qt-everywhere-opensource-.*/bin%/bin%' \ /usr/lib/pkgconfig/Qt*.pc