The PHP getting started guide for interacting with Force.com seems to indicate that a user always needs to reauthenticate for each session with OAuth2, and that's my understanding of the protocol as well.
However, if a user just wants to be able to interact with APEX REST Methods without requiring the user to authenticate, they would use session id style authentication right...? Anyone know where the documentation to do this is via web-service calls in PHP?
Update
Like using a fixed set of authentication credentials to access the APIs