Windows XP/2000 only: Software firewall ZoneAlarm is offering free downloads of its basic firewall package with a spyware scanner/cleaner and a year of free updates until 5 PM PST today (although you’ll get an email with a download link that’s valid for a week after that). Program maker Check Point Software claims the free offering is made to coincide with Microsoft’s monthly “Patch Tuesday” and the ensuing new vulnerabilities that hackers start working on. Regardless of the…