Short answer: No, this can't be used anymore, are you blind? Read the great big text at the top of the page!
Longer answer: This hack was broken well over a year ago. Making it work now is extremely difficult and probably not worth the effort, even if possible. However, if you really want to try, you'll need to meet all of the following conditions:
* Your phone is a gen1 WP7 (HD7, Surround, 7 Pro, Mozart, Quantum, Focus, Omnia 7, Venue Pro, and a few others, but *NOT* gen 1.5 phones like the Arrive)
* You have a very early stock ROM for your phone (build 7004 or 7008 are the only ones that are known to work).
* You are able to flash that stock ROM (this requires a flashing too that varies depending on the OS and a working flashing mode in the bootloader, or a Zune restore point for one of those builds).
* You are willing to hard-reset your phone, or at least revert it to the state of your 7004 or 7008 backup (if that's what you have; if you flash a stock ROM you'll lose all data).
* You've downloaded the ChevronWP7 Unlocker tool and its certificate (no idea where you can get working links to them; maybe somewhere in this thread but I haven't tried).
* You understand how to set the clocks back to make the expired certificate work.
* You don't mind either staying on pre-NoDo, or you have a way to re-dev-unlock as you upgrade (certainly Mango, and I think also NoDo, will reset your hacked dev-unlock).
If you have all that, go to town. Personally, I suspect that's not worth $99 of my time and effort, so I'd probably just get an AppHub account instead, which will give you the exact same level of unlock...