From: "Geo." 

http://www.microsoft.com/technet/security/bulletin/ms06-001.mspx

patch is available for W2K, XP and 03

Win9x, ME, and NT3-4 users are SOL...

How does the extended support for Windows 98, Windows 98 Second Edition,
and Windows Millennium Edition affect the release of security updates for
these operating systems?

For these versions of Windows, Microsoft will only release security updates
for critical security issues. Non-critical security issues are not offered
during this support period. For more information about the Microsoft
Support Lifecycle policies for these operating systems, visit the following
Web site.

For more information about severity ratings, visit the following Web site.

Are Windows 98, Windows 98 Second Edition, or Windows Millennium Edition
critically affected by one or more of the vulnerabilities that are
addressed in this security bulletin?

No. Although Windows 98, Windows 98 Second Edition, and Windows Millennium
Edition do contain the affected component, the vulnerability is not
critical because an exploitable attack vector has not been identified that
would yield a Critical severity rating for these versions. For more
information about severity ratings, visit the following Web site.

--- BBBS/NT v4.01 Flag-5