I have seen on several sites that are very tall, they have adsense in a side bar that scrolls with the page. This is cool because even if you have a super long page the adsense is always visible. My question - Is this allowed by google?

I will try to get an example site. Thanks in advance - John

Yes, it should be allowed. The moving aspect is usually just acheived with the CSS 'position: fixed'. Because this is normal positioning, as set out in an internationally agreed standard from the w3c, I can't see any reason for them to deny it's use.

Secondly, it's not like it breaches any of the usual rules (tricking people to click, et cetera).

OK, I figured that was the case but I thought I would ask to make sure. Thanks for the reply alex.

I think it would be legal too, but when in doubt ask Adsense. They're more than happy to answer these questions.

No problem John. I second feros' wise suggestion - an email to them would be a good idea.