How well protected is Windows 7 from spyware? What free clients are available? Do the clients for Windows Vista work at all with Windows 7?
Windows 7 is not fully released yet is it? Therefore I wouldn't think there was any. I might be wrong.
Strike that here is a list of antispyware software compatible with windows 7
Most all programs compatible with Windows Vista (and even XP) are compatible with Windows 7. This would include anti-spyware apps.
... and of course there is always Windows Defender which is a feature of Windows 7 (as well as Vista)
Free, specifically designed for Windows Vista and 7, built by Microsoft, working fine on my Windows 7 RC.