Mobile Setup: Windows Phone 

Options for access

Set up your Windows Mobile phone with Google Sync to access your Google Apps mail, contacts and calendars from your phone's native applications (requires that your Google Apps administrator enables Google Sync for your domain). Learn more about Google Sync
Access other apps such as Docs and Tasks from your phone's browser app. Just point the browser to m.google.com, touch the app you want to use, and sign in to your Google Apps account.
Mobile apps overview

Here's a look at just a few of the apps you can use on your Windows Phone!

Gmail Send and receive mail.
Google Calendar View and add calendar events.
Google Talk Send instant messages.
Googe Docs View docs.
Contacts Access and update contacts.
Tasks View and add tasks.