Just a quick sidenote here. I’m working on a Rooting 101 article, but I wanted to briefly explain why a Bootloader is different from Rooting.
A bootloader is the part of a device that controls what Operating system is run. As a default, it’s configured to run ONLY operating systems sent out by the handset maker for that device.
The Recovery image is the command line basis for that operating system, allowing you to update the OS, load a new one, or do a factory reset.
For most phones, if you have root access, you can change this recovery image to allow you to install custom builds of the operating system and not just carrier approved versions.
On devices where the Bootloader is digitally signed (Like the Droid X/Milestone), having root access will not allow you to flash custom roms as a default. First a developer needs to find a way to hack the boot oader into accepting non-approved updates. This is very difficult, so if you have one of these devices, rooting might be a bit of a ways off for you.
