The system is set up to be easy. At the end of each month, the amount of money each app earns via sales is calculated. 70% of that number is computed and if that number equals or exceeds $200, an Electronic Funds Transfer is made to the developer's bank. The problem is that some developer's accounts are listed as "Not eligible" when they should be listed otherwise. On the other hand, even if the developer tells Redmond that there is a mistake, it doesn't guarantee anything because even some developers who have accounts eligible for payouts have not received a dime since the October start-up of the Marketplace. With the momentum that the iPhone and Android have had and the number of apps on both far exceeding what is available for Marketplace for Mobile, Microsoft needs to get this straightened out in a hurry.
source: arstechnica via BGR