Although Nexus One is not available via Google’s online store any more, those of you who own the device or will get it via a carrier are now able to root the device with a single click. The process is much easier than the one used for other Android handsets and the process won’t have you worried about bricking the handset.
The exploit involved in this hack is the same one used to root Moto Droid X (by using UniversalAndroot). UniversalAndroot supports a couple more Android devices, as well and the app includes unroot features, plus it’ll help you install custom ROMs. It’s all free and detailed here.