Remember when the Dual Shock 3 came out? Quite a few patches were released, although most of them from Sony titles enabling you to enjoy rumble in games that had already been released before the controller was out in the wild. All those patches were free. With the PlayStation Move controller though, it will be up to the publishers to decide if there is a fee for the patch. We can assume the Sony published titles will have free Move patches, but other companies like Capcom and EA, could very well charge money just for a patch to enable Move support.
From the US PlayStation blog:
Q: Will I need to update my games to enable PlayStation Move support? If yes, will it be free?
A: Most PlayStation Move games you'll play will be designed specifically for the motion controller, though some game publishers have chosen to add PlayStation Move support to their existing PS3 games. Resident Evil 5: Gold Edition and Heavy Rain are two well-known examples of existing games being adapted for PlayStation Move. In these cases, you will download an update over the PlayStation Network to add PlayStation Move support. Whether these updates are free or will require a fee will depend on the game and publisher.