From the Admin Site Map, go to:

• Reports, > Report Exports
• Click on the Account Information report
• Click the Primary Accounts checkbox
• Move the Account Balance data field from the left column to the right column
• Click Export

This will pull account balances for all accounts so you will need to sort the data and remove the accounts with $0 balance.

You can also easily send communication to all accounts with a balance owed by going to Communications > Send Communication. Open the Customer Accounts distribution list and select All Accounts with a Balance.