There were some rumours on Thursday that Windows AntiSpyware wouldn't stay available for free but this is false according to a Microsoft employee:
As we have been saying since day one, Microsoft Windows AntiSpyware will be available at no charge to licensed users of Windows. Users who validate their Windows install through WGA will be allowed to download the AntiSpyware beta, as well as the full standalone version of AntiSpyware when it releases to the web. This has not changed since Bill Gates announced this information at the RSA conference in February.
The enterprise version of Windows AntiSpyware is targeted to companies who want to centrally manage their Windows AntiSpyware infrastructure. The enterprise version of Windows AntiSpyware will be available for a cost (which has not been determined yet).
For users who want more services including AntiVirus, computer backup, and AntiSpyware we will be offering Windows OneCare live. Windows OneCare Live is currently in beta, but when it releases to the web it will be available to users with a cost.