According to Microsoft, here are the changes that are pending for MS Antispyware:

• It will be rebranded as MS Defender
• Updates will be distributed through Windows update, instead of separately through Defender
• Defender will be a part of Vista, Microsoft's new operating system
• Defender for Windows XP will be available, but Microsoft is unsure of the release date
• Its capabilities will be broadened to include detection of rootkits, keystroke loggers and other threats