We've just uploaded iJailBreak 0.5.3 to our Google Code. This version brings a few features from the new ZiPhone version released a short bit ago.
First, the unlock now works on all iPhones - regardless of whether you bought it this afternoon or on June 29. Second, we got some conflicing reports from our PowerPC users regarding iJailBreak working - some said it worked, others said it didn't. This update has re-ensured PowerPC compatibility for those running Tiger or Leopard. If you're running any other version of Mac OS X, iJailBreak will not work.
IMPORTANT: this release does not include iPod Touch support. We're still working on that.