The 3.0 firmware for the iPhone 3G S is now available for download on Apple’s website: iPhone2, 1_3.0_7A341_Restore.ipsw
Installing it on your iPhone 3G won’t give you video recording or copy/paste. No, unfortunately it’s pretty useless for the time being as it can only be uploaded on an iPhone 3G S. So don’t waste your time downloading it and trying to install it on your iPhone.