Exactly. Microsoft Antispyware will be renamed Windows Defender, and
included in all builds and SKU's of Vista, and available as a separate
download for XP and Windows Server 2003. No statement has been made about
Windows 2000.
Microsoft Client Protection:
http://www.microsoft.com/windowsserversystem/solutions/security/clientprotection/default.mspx
On the home product side, there is also Windows OneCare Live:
http://www.microsoft.com/windows/onecare/default.mspx
which will eventually include the antispyware capabilities of Windows
Defender.
Windows Defender will be free--i.e. cost covered by the original license
payment for the OS. Microsoft Client Protection and Windows OneCare Live
are both purchasable. Details aren't available yet, but I suspect that both
will be subscription-based.
OneCare is in beta now, Microsoft Client Protection likely to be in beta
soon.