KZoom can be downloaded both as source code or binary form. You can access latest version of KZoom on download page.
To compile it you need at least KDE 3.x and Qt 3.x. It is necessary to have KDE and Qt development stuff instaled (KDE headers, Qt headers, Qt utilities) and GNU C++ and friends (g++, gcc, binutils etc.)
Bellow are convenient links for you.
KDE 3.1 / Qt 3.1
Nothing yet available.
KDE 3.0 / Qt 3.0