We recently had a news that latest and most updated iPhone OS 3.0 has been exploited and the culprit is its WiFi feature. Recently experience exploit is remote execution WiFi exploit using karmetaspolit which is executed unknowingly on the victim without any interaction. Following is the video posted by iPhoneworld.Ca
iUsability-Pwned from Max Moser on Vimeo.
Tags: iPhone 3.0, iphone-hacks
yes you are right, there are different which are not compatible with iPhone 3.0 but few of them get updated like Vopium and Jailbreak