Valve have again released new anti-cheat modules for Counter-Strike and Day of Defeat:
We've updated the public security modules again. If you've been helping us test the beta security modules, you should remove the password from your
command line and restart your server. The beta security modules are no longer being tested.
These security modules should detect most versions of OGC and report detected cheaters to our ban list server.
The latest developments on the HLDS mailing list are somewhat interesting; there is currently some contention about whether the proposed VAC system is going to be a good or bad thing. Valve's idea is to run a central banning system for cheaters which will simply ban any WONID connecting with a cheating incident. However, they have not made any comments about how people will be able to find out why their WONID is banned - that is, the ban list will be managed by Valve and no-one currently knows how or even if admins or players will be able to get information from them about banned WONIDs.