Android 4.2.2 JDQ39 roll out started couple days back when the Nexus devices started receiving the OTA update. Some of the users are yet to see the update though. For those who want to install the update immediately, they could download the OTA update and install it on their rooted / non rooted devices from Recovery menu.
GSM Galaxy Nexus takju devices starting receiving the update almost immediately and the download link also became available soon after for those who had not received the update. However, yakju users were not so lucky as they neither got the OTA update nor saw any download links to get the update manually. The wait is over now though, as the Android 4.2.2 JDQ39 direct download link for Galaxy Nexus yakju devices has finally become available now.
Download Android Jelly Bean 4.2.2 for Galaxy Nexus (yakju)
Direct Download Link: yakju-JDQ39-from-JOP40D.07501b11.zip
After downloading the zip file, you can install it by following this guide: How to Install OTA update manually with CWM / Stock Recovery.