Windows XP Firewall inventory / query

Hi all,

I need to find out the Windows Firewall status on all my machines, to see which ones have it enabled. 

What's the best way of finding this, and querying it?  It doesn't seem to be in the default inventory.

I've tried adding a line to the LDAppl3.template file under reg settings as follows:

KEY-HKLM, SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\, EnableFirewall, XP settings

and clicked 'Make available to clients' but it doesn't seem to produce any results.

Any ideas??  Many thanks,

Charlie.