Floating block - Critical

[Dooq]

I want one of the content (Adv) to be floating in the page.
When the user scrol down I want it to goes down auto.
Like the Adv in the right block here demonoid.com

[code]<div class='adv'>Hello World!</div>[/code]

can any body tell me what should I but in the adv CSS style

[Ricklord]

Could you use position:fixed; ?

I think this works in FF but not to sure about IE.

Rick