Hi dboy1,
Welcome to CrowdSupport,
Telstra Mail can import iCal files in .ics format and contacts in .csv or .vcf formats within the webmail page.
Webmail for Outlook.com will allow you to export your contacts in .csv format.
If you are using an email program to manage both mail configurations, then you will need to refer to the software vendor for assistance with this. In the case of Outlook Express, you will need to contact Microsoft for assistance.
The following link is helpful for customers migrating to Telstra Mail.
https://www.telstra.com.au/support/category/email/telstra-mail