I knew you would ask about how to setup the screen-saver module!
The kerneld/GOODIES directory in modules package has a couple of kernel patches for screen-saver and console-beep support in kerneld; these are not yet part of the official kernel, so you will need to install the kernel-patches and rebuild the kernel.
To install a patch, you use the patch command:
cd /usr/src/linux patch -s -p1 /usr/src/modules-*/kerneld/GOODIES/blanker_patch
Then rebuild and install the new kernel.
When the screen-saver triggers, kerneld will run the command /sbin/screenblanker; this file may be anything you like, for example, a shell script that runs your favorite screen-saver.
When the kernel wants to unblank the screen, it sends a SIGQUIT signal to the process running /sbin/screenblanker. Your shell script or screen-saver should trap this, and terminate. Remember to restore the screen to the original text mode!