This portion of the Documentation Handbook is incomplete. Please be patient as documentation of omega is an all volunteer effort. We are planning more sprints and hope to have the entire handbook completed very soon. If you'd like to help in our efforts to complete comprehensive documentation for Omega please join us in IRC @ #drupal-omega where the majority of doc planning is done in real-time.

Until then you can find more about the 960 grid at its project site 960.gs. And, read about the responsive web from the A List Apart article Responsive Web Design.