The official Google Drive app for linux is not yet released. But there are third party options. InSync is a really good option.
Download the Insync.tar.gz from
http://s.insynchq.com/builds/insync-linux-beta1-py27.tar.bz2
Extract to your Home folder
Open a new terminal and navigate into the extracted Insync folder using the ‘cd’ command (e.g. cd insync/)
Run: sudo ./insync-installer
Follow any on-screen prompts
After installing there are a few other things to note:
Insync must be started from the Terminal by running ‘insync’
The app doesn’t auto-start by default, and there is no in-app way to enable this
Source : OMG!UBUNTU!
grive, since it's free in RMS-kind-of-way. – aL3xa Oct 19 '12 at 14:41