You can find your Salesforce Organization ID from either Salesforce or Cirrus Insight.
Salesforce
- From Salesforce, go to Setup
- Under Administer, select Company Profile and then Company Information
- Find the ID in the field Salesforce.com Organization ID
Cirrus Insight
- From your inbox, go to Cirrus Insight Settings (wrench icon)
- Select Account Information from the menu on the left
- Find the ID in the field OrgID