Limits time playing installed game software (and also online browsing)

I'm looking for a non-subscription freeware (preferably) utility which will restrict the time spent by my kids addictively playing games (or other chosen software titles).  Apparently Windows Vista already comes with such parental control features, but I'd like to get something similar running on my Windows XP Home and MCE systems.

Preferably, there would be features included such as those of the commercial products summarized in the table on this page:  http://parental-time-control-software-review.toptenreviews.com/

Such features would include separate controls for different individuals (might require separate user accounts, rather than a single "KIDS" account like I'm now using);

schedules/limitations by each day of the week, or at least for weekdays vs. weekends;

time limits for each "user session" as well as total playing time per day and week;

preferably separate scheduled restrictions for specific software titles (installed games, like Warcraft), and also on separate web sites (e.g., to allow more or unlimited time on homework sites, less on others like YouTube videos);

remaining-time display or pop-up warning (to allow saving place/progress in an online multi-player game); etc.

I think another user was asking for the same thing on this page, but instead got recommendations for Internet-only software:  http://www.techsupportalert.com/content/parental-control-application.htm

Thanks!