I just installed Debian Squeeze and it defaulted to the gnome desktop environment. I have installed KDE via the package manager but do not know how to set it as the default environment. Any help would be appreciated.
You can choose what Desktop you want during log-in. That is, instead of just entering your username and password, go to something named along the lines of Choose desktop session and select KDE. From there, proceed to entering your username and password, and you should find yourself inside of a KDE desktop.