Now we have both a fresh version of Spirit like all iOS device userland jailbreak, and unlock for iPhone 4 ready. The wait is probably for Apple to release the next firmware update (iOS 4.0.1 / 4.1 for iPhone 4) before these jailbreak and unlock tools are made available for public use.
According to a recent tweet published by the DevTeam member planetbeing, he and MuscleNerd have finally managed to unlock iPhone 4 using the ultrasn0w tool by DevTeam, thus allowing it to be used on any GSM network worldwide.
My soft-unlocked iPhone 4 (in Canada). I’ll have video in a couple of hours once I can top-up the SIM http://twitpic.com/24ycdv