Ubuntu Guide posted a tutorial about installing Insync for Linux in Ubuntu using PPA

Insync is Google Drive for power and business user. It supports multiple Google accounts, offline Google Docs editing, right-click share, recent changes notifications, non-admin Windows install, external hard drive support.

Insync for Linux is still in beta release, it has been tested in Ubuntu 12.04 and Linux Mint 13.

  Install Insync Google Drive Client in Ubuntu 12.04 & 12.10