If you search, there's
another thread about the Google Desktop Seach Tool.
However, addressing the spyware issue:
Yes, there is a security issue if you're on a multi-user PC (it will index all content, regardless of who owns it). However, if you're the only person who uses a PC, Google isn't going to divulge your information to third parties, etc.
It's a search tool - the
point of the tool is to search your harddrive for content, index it, and let you search it - that's why you installed it. Sure, it might show ads based on what content you have, but it doesn't submit a giant list of content to Google and let them go "hmm, I think we'll show this ad." You're not going to have to worry about spyware from Google, and I can promise you they won't violate the privacy policy - they'd have way too many pissed off people.
The whole spyware thing reminds me a bit of how people started screaming that GMail was going to have ads. I've used GMail since almost the day it came out and I
think there are ads, but I never notice them
