Login to your ServiceM8.com account, go to the Settings menu.
Click ServiceM8 Add-ons
Activate the External Calendars add-on by clicking the switch
Configure External Calendars
Click the Settings button to get your external calendars URL
Each staff member has their own calendar url, you will need to repeat the process for each staff member's schedule you wish to see in your calendar.
Select and copy the entire URL for the relevant staff member.
Configure Microsoft Outlook
Select the Internet Calendars Tab, and then click New...
Paste the URL you copied in the above steps, and click Subscribe.
That's it. You should see your ServiceM8 schedule appear in your calendar in the next few minutes, repeat the process for each staff member's schedule you would like to see.
NOTE: You are not able to make changes to your ServiceM8 Schedule, only view it. To make changes you must use the ServiceM8 Dispatch Board, or the iPhone/iPad app. Also be careful of recent changes, as while MS Outlook is kept in sync with your ServiceM8 Schedule, it's not real-time - so recent scheudling changes may not be reflected.