You can access email, instant messaging, Office documents, and other Office 365 services from your Android phone. Instructions for setting up your phone are included here and in the Office 365 portal. Go to Settings > Office 365 settings > Get started > Phone & tablet. Or, you can go to Software > Phone & tablet. Choose Android Phone.
You can also install the Lync (Lync: An Office program that provides instant messaging, a contact list, audio and video conversations, online meetings, desktop sharing, and more.) app from the Office 365 portal, or go to Android Market.
Set up email on an Android phone or tablet
Use Office Web Apps on your Android phone
Lync for mobile clients
Open a SharePoint Online site on an Android device