As expected iPhone 3GS jailbreak dubbed Prurplera1n is out now and you can use it to jailbreak the latest iPhone running iPhone OS 3.0, despite iPhone Dev Teams warning to hold the jailbreak until iPhone OS 3.1 gets out, "GeoHot" went public with the jailbreak stating that this is not the last hole and this is the way this works - we release, Apple fixes, we find new holes.
Jailbreaking allows you to customize your iPhone with home-screen wallpapers, third-party ringtones, themes and above all enjoy applications and hacks available via Cydia installer, The Windows only Prurplera1n jailbreaking utility for iPhone 3GS is surprisingly just 394 KB in size, and needs no IPSW files to jailbreak your phone, follow the instructions ahead to jailbreak your Apple iPhone 3GS.