It looks like they stopped the ability to earn free miles some time ago, from text such as the following:

"eCheck Express payments can be accepted by all Personal accounts with no fees. Credit card payments are only accepted by Professional accounts."

and also:

"Effective June 1, 2004, For Professional accounts we are charging a monthly fee of $5 dollars. However, the per transaction processing fee of 2.5% plus $.30 for every transaction received into your account. Will change to 2.4% plus $.30 cents. We automatically calculate and display these transaction fees before you receive the money, so you'll always know the cost in advance."

From the Paydirect FAQ:
http://help.yahoo.com/help/us/paydir...manage-01.html