The quest for this started in an effort to be more organised and trying to have everything in one place. In my case it was my iPod Touch.
In our office I realised that we are restricted to install iTunes which would have made things pretty easy but continuous search for a solution gave me the exact steps required. I hope someone else will also be able to benefit from this, so here are the steps:
When you install it like me you might get an error for Windows Time Zone not being right and that is where this link comes in handy: http://support.microsoft.com/gp/dst_hu1
(Just install the update on the second step of this link and dont bother going any further.)
So its Outlook > Google Calendar > iPod / iPhone and reverse meaning you add anything to iPod calendar is added to your Outlook too

Enter Account Info
5. In the Email field, enter the name of the account (anything you’d like).
6. Leave the Domain field blank.
7. Enter your full Google Account email address as the Username.
8. Enter your Google Account password as the Password.
9. Tap Next at the top of your screen.
10. A new Server field will appear. Enter m.google.com.
11. Press Next at the top of your screen again.

12. Select the Google services you want to sync. Currently only Contacts and Calendar are supported.
Make sure that you have uploaded your data before proceeding.
13. Press Sync twice when warned about data loss.

You’ve set up Google Sync for your iPhone. Synchronization will begin automatically if you have Push enabled on your phone. You can also open the Calendar or Contacts app and wait a few seconds to start a sync.
Tip: If your business, school, or organization uses Google Apps, your administrator will first need to enable ActiveSync before you can take advantage of this feature.