X10 makes two pieces of software that record
to hard drive: Vanguard Internet Control
Center, and iWitness for ActiveHome Pro. Both
are designed around the idea of saving video
when motion or other events occur, rather
than the continuous recording of a dedicated
DVR system. You can use an X10 camera system
with any hard-drive based system on the
market that accepts standard RCA video inputs.
Depending on how you want to do things, using
the wired cameras (either the regular wired
cameras or a Vanguard camera with a wired
connection) may be the easiest for managing a
multi-camera system with constant video.
Using wireless cameras requires constant
switching at a fairly low rate by comparison.
If you have specific questions I can answer,
I'd be happy to help.