Option A - Set up a forwarding rule.
The details might vary a bit by Outlook version, but here is how to do it in Outlook 2013.
- File menu --> Manage Rules & Alerts.
- E-mail Rules tab --> New Rule...
- Start from a blank rule, Apply rule on messages I receive.
- Find and check "which is a meeting invitation or update".
- Accept the warning about incompatibility with previous versions.
- Find and check "forward it to people or public group".
- Click on the "people or public group" link and select or create your external e-mail address as the recipient.
- Select any exceptions.
- Give the new rule a name and select whether to run it on existing messages.
Caution: Before implementing anything like this, you should talk to your Legal Department. Many regulatory and compliance requirements forbid the storage of company information on non-company devices and/or the forwarding of company e-mail to personal e-mail accounts.
Option B - Talk to your IT Department about the supported way to use your personal phone to check your business e-mail and calendar. They might have already implemented one or more solutions like Outlook Web Access, ActiveSync, Blackberry's Good for Enterprise, or Citrix's (XenApp) Secure Mail.