Hi Marmot80,
Have a look here;
Bigpond.com - got to 'My Account' - Click on your email account - you should see an option for forwarding, there is also a useful option to forward and not keep a copy which you may find helpful.
*Note, it may re-direct you to the new Telstra My Account page. If this happens, go back to bigpond.com and back to 'My Account' again.
Nick