How to best integrate Zoho email, calendar, project,etc. with Google (non-enterprise) apps

How to best integrate Zoho email, calendar, project,etc. with Google (non-enterprise) apps

I currently use Gmail, Calendar, Docs, Sites and Groups to collaborate with partners external to the company. I also have begun to use Zoho projects to complete projects with these partners.What is the best way to integrate Zoho and Google so that my Gmail, Google Docs, Google Calendar, Google Groups and Google Sites are incorporated with Zoho so that I can access all these apps within Zoho?

Thank you