I have the google logo on my website near the adsense, is this illegal? I dont think it would but you never know. Its on top of the 468x15 (5 link) banner along with other jpg's that are horizontal across the top of the bar.
Though I can't comment on the ToS issue, I'm very sure that it could be viewed as Trademark infringement. Google and the Google Logo is a registered trademark, so they might take legal action because you are using their trademark (though it will depend on the usage). Best to e-mail their support and ask if that is allowed.
The post above makes it quite clear. I wouldn't imagine there are many companies out there who would allow the use of their branded imaging.
I have removed it for now and await an email from google. The space I have available is a small 70x50 area above the Ads by google writting. Thx