If you have a look at these pages, you will see that it’s pretty straightforward: look for the firmware you want to jailbreak/unlock, then choose your device (2G, 3G, or 3GS) and click on the appropriate guide.
I decided to create these 2 pages because it might be a little hard for newbies to figure out what they’re supposed to do or even how to search for information on this blog. This way, I make it dead simple for everyone to find relevant and clear information on both jailbreaking and unlocking the iPhone.
Note that I am starting this page with the latest 3.0 firmware. By now, most people have updated their iPhone to 3.0 and it wouldn’t make much sense to list previous tutorials I wrote.