It’s very easy to sync your Windows Mobile 6.5 mobile device with Google Calendar, Gmail and Gmail Contacts.
However, Google needs to fill in an empty “domain” field. And within WM6.5 the “next” button is disabled,
when the domain field is empty.
I tricked it, and it works!

Here’s what I did:

1. On your device, open Active Sync
2. Tap: setup your phone to sync with it
3. Fill in your google email address – tap ‘next’
4. Fill in your google username and password.
5. According to Google. The domain field needs to be empty.
   However WM6.5 does not allow an empty domain field. So fill in: m.google.com.
   Now the “Next” button is enabled. Tap it.
6. Fill in the server address: m.google.com
7. Check SSL, tap “Next”
8. Uncheck Tasks and Text Messages. (When you leave it checked, syncing with Google won’t work!)
9. Tap: “Finished” and try sync your device!
10. Since the domain field, needs to be empty, you will be prompt back with the connection form.
    Remove the “m.google.com” and press an empty “space” with the spacebar key in this field.
    Some how, now finally WM6.5 recognize m.google.com, so now it will sync and work.
    (please note, by prefilling the spacebar already in the begin of the process, won’t save your
    settings, so you have to start over these steps.)