And not let Google know about it? Or do I have to contact Google and get the new site approved? Thank you all.
Only make it sure that your new website does not violate Google's TOS for adsense. If unsure, it will be better to contact them
Yes in fact you HAVE to use that same account accross your multiple sites as creating multiple accounts within a single billing address represents a violation of the TOS. Keep in mind though that an advertiser that wishes to ...advertise on your site by clicking on the "Advertise on this site" link in the lower right part of the google ad unit will be brought to a default landing page that will (by default) display your MAIN website to which you first linked your adsense account to. see my thread here @ http://forums.digitalpoint.com/showthread.php?t=210428