Hi,
I assume your Debian system is running fine - but without X -, you installed from the stable tree and your machine is connected to the Internet.
Then the most simple way to get an X-server running, is to install e.g. kde.
Code:
apt-get install kde
If you wan'na use another windowmanager, just replace 'kde' with the name of the package.
If you wan'na do it from scratch, post a message. This will need a little more information.
Hope I can help you so far ...
bluebirdz