Google has been rolling out integration of your AdSense data in Google Analytics since October, but many publishers still wish they had it. If you do not have it yet, you can now get it.
AdSenseAdvisor posted a WebmasterWorld thread said you can get it by going to the Inside AdSense Blog and reading the top. The top basically says:
Want to integrate your AdSense account with Google Analytics? Improved reporting was on publisher wish lists this year, so we're spreading the reporting cheer this holiday season. Fill out our interest form, and we may be able to enable the feature earlier for you.
So if you want your AdSense integrated in Analytics, quickly go to the interest form and fill it out. It will then add your name to the list and you should get it soon.
AdSenseAdvisor said this is a Happy Holidays present to publishers. So take it while you can!
Forum discussion at WebmasterWorld.