Inside Microsoft Dynamics GP’s newest Feature of the Day for GP 2010 covers improvements to the Billing Frequency Options on Contracts in the Field Service module.
GP 2010 Feature: Billing Frequency Options on Contracts
Off-Topic & MiscellaneousGP 2010
Archived post from 2010. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.