Do you mean the MediaSmart Windows Home Server?
If so, not at this time. Since OneCare only runs on XP and Vista, it won't work on WHS which is actually Windows Small Business Server 2003 at the core.
I know that there are ongoing discussions about better integration between WHS and OneCare, but at what level and how far away, nothing at all has been announced. My guess is that it is a long way off. I'm ready to test it as soon as they are ready, though. :-)
-steve