According to recent tweets from members of iPhone Dev-Team, the all new ultrasn0w which has been written again from scratch for unlocking iPhone 4 is all set and ready. The wait now is probably for comex to package and release the new all iOS device jailbreak so that this new ultrasn0w can be released for iPhone 4.
iPhone 4 Unlock
Planetbeing: We’re gonna be able to give you an unlock with the jailbreak.
Planetbeing: It will probably be the usual thing where you jailbreak and then install ultrasn0w from Cydia.
MuscleNerd: @Gangstatyzz hmm just staying the unlock is ready now, for whenever the public JB is done + debugged + packaged
I personally think we are really very close to a public release of an all iOS device jailbreak. Stay tuned as we will let you know as soon as it is ready for download