If you want to use Outlook with your Google Apps account (however we recommend to use Google Chrom webbrowser to get use of all collaboration functions), please download the Google Apps Sync for Outlook plugin.
After installing, you will be redirected to a webpage where you have to enable the sync function (authorization).

The plugin creates a new user profile in Outlook. During this profile setup you will be able to import the existing data from your Outlook to tour Google Apps account.