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.
It will be pushed as an update in the next few hours to our current install base, but if you'd rather use iJailBreak 0.5.3 now, you can download it here. Enjoy!
UPDATE: Intel/PPC Tiger systems don't work with 0.5.3 anymore. We'll attempt a fix soon.