I did it using Spirit on a Mac. It’s definitely easier now than the iPhone OS 2.x era — that is, no more of setting the phone in “Restore mode” and running a bunch of commands.
This time it was as easy as downloading, running the app, and clicking the “Jailbreak” button, which, by the way, took less than a minute to complete. Once done, the iPhone will reboot and it’s back to normal.
Check it out. Happy iPhone’ing!