1. Open ZiPhone 2.5
2. Click to display advanced features
3. Select jailbreak, activate, and unlock
4. Press perform actions
5. Let program run
6. Close ZiPhone 2.5
7. Open ZiPhone 2.3 or less
8. Select the unlock option
9. Press start
10. Done. This is assuming you have 1.1.4 installed
see the full thread here.