The folks at Landis Computer have enhanced their very nice Dynamics GP Productivity Pack to now include the ability to dial phone numbers directly from GP for various IP phones. More information is available on their blog post Free Addon Add’s Dynamics GP Click-To-Dial Functionality With Most IP Phone Systems.
Free Addon Add’s Dynamics GP Click-To-Dial Functionality With Most IP Phone Systems
Archived post from 2010. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.