Talderon, thank's for the dummy explanation

While we are on this, I see posts asking how to 'unroot' one's rooted phone. I thought that once rooted...you can't 'unroot'. Flashing your phone with the stock Recovery ROM doesn't seem like 'unrooting'. So can you unroot a rooted phone?
You can "unroot", but you can't lock the bootloader once it's been unlocked.
How do you 'unroot'? So if you root without unlocking the bootloader...when you 'unroot', your phone will be just as it was before you rooted it?
OK, I guess I should have put this in the explanation above.
Simply, what is Rooting and Unlocking the Boot Loader? Same?
Simply put, NO.
Unlocking the Boot Loader is NOT ROOTING.
Unlocking this means you are removing the security check that validates the recovery image installed and also keeps you from flashing anything that is not signed with a Google Key.
Rooting:
Android is a LINUX based operating system. Which means if you are Linux savvy, you would understand some of these terms and what they mean/imply.
ROOT is the administrator/god account that allows you to do pretty much anything to your operating system. Everything from removing stuff, adding stuff and of course, screwing stuff up.
This is also known as SU or Super User level access.
Some commands/operations that allow you to access/modify core system files or what the OS Dev locked down as system/core files and commands, you cannot modify in any way unless you have Root/SU access.
I hope this clears the air some more.
To answer your questions:
How do you Unroot?
You just re-flash the stock ROM. Nothing more complicated than that.
Can you re-flash the stock recovery?
Yes, but I won't get into that on this post. Let me know if you want to know how.
Can you re-lock the boot loader?
At this time, no. The ONLY way you can is if you happen to be lucky and have the holiday nexus one with the S-OFF option in the boot loader (which 95% of us don't have).