Edit Poseidon: Well guys... Apple finally patched the exploit in the bootrom that has been allowing redsn0w and pwnage tool to work. There are now new 3GS iPhone in the wild that have a new version of iBoot that will not be jailbreakable until a new exploit is found! Better hurry up and buy em while you can... may not last long.
"@MuscleNerd @geohot @iphone_dev There is a new iphone 3GS Bootrom iBoot- (24kpwn no workie)" - Mathieu Hervais
"yay! new 3gs bootrom apparently kills 24kpwn." - cpich3g
"oh oh, from what @cpich3g + @Mathieulh have found so far, a normal untethered JB may be in jeopardy in brand new 3GS units" - MuscleNerd