What you do to your phone is your responsibility. Following this procedure *will* void your warranty. It could also break your phone. We will not promise technical support, though you may find help in the forums. If you want Sense on your Nexus One, proceed with caution.
I’ve gone back and forth on the topic of rooting my Nexus since I first heard it was possible. At first, I didn’t see much benefit over a stock configuration. But as the hacks got cooler and the ROMs got hotter, I found the prospect difficult to resist. So here’s a video of me doing it for the first time. Click each link below for the instructions and files required for each step:
Step 1: Unlock the bootloader
Step 2: Root the phone
Step 3: Replace the recovery image (it is highly recommended that you back up the stock ROM after the recovery is installed).
At this point, you need to wipe your phone. If you flash the ROM without wiping immediately beforehand, you will not be able to boot and will need to restore your nand back-up, wipe, then flash the ROM. This is covered in the video at the appropriate time.
Step 4: Flash the ROM. (Read what Paul tells you to, folks.)
See the whole process on video:
My sources are the pages linked to in this post, pretty much everyone who cooks Android ROMs, and many, many great folks on Twitter.