You should have gone through and did a basic X configuration when you installed...
Wait. no. I'm lying.. it uses X4...
Try just typing startx and see what happens...
"xwmconfig" will open up a script that lets you choos your window manager (Gnome, KDE, Enlightenment etc)...
If just typing Startx doesn't work, su to root and type "xf86config"
Make sure you remember your monitor specs
-M