Using Google Apps on an Android is really easy. Just add your Google Apps account to the phone, then select the services you want to use. Each user should follow these instructions on their own phone.
1. Open the Accounts & Sync Settings screen on your phone. You can do this in Contacts by pressing Menu and touching Accounts, or directly in the Settings application.
2. The Accounts & Sync Settings screen displays your current sync settings and a list of your current accounts.
3. Touch Add account.
4. Touch Google to add your Google Apps account.
5. Touch Sign in when prompted for your Google Account.
6. Enter your full Google Apps email address as your username, and then enter your password.
7. Select which services you’d like to sync between your phone and Google Apps.
That’s it! You can now use Google Apps from your Android.