Just yesterday there was a rumor floating around that Android 2.3 (Gingerbread) might never come to the Nexus One. The thought was that 2.3 would remain a Nexus S exclusive while all other phones would get the 2.4 version of Gingerbread. Looks like that was wrong. The @GoogleNexus Twitter announced last night that the update to Android 2.3.3 has begun rolling out to the Nexus S and Nexus One. As the tweet says, this update may take a few weeks to roll out over the air to all owners of these handsets, so patience is key (until we track down a manual install).
The update brings along some new NFC goodies including the ability to write your own tags (which will be of no concern to Nexus One users) and it also deals with the random reboot issues owners of the Nexus S have been experiencing.