php sessions and classes

hi, i'm busily rewriting an exisitng calendar system that is in use at work. we're using UML as a design tool and hope to have an OO version of the system we have at the minute that wil 'fit in' with future devs. our system at the moment makes heavy use of postgresql and i am hoping to populate various object from the data in the db. our system also relies on session for passing data between pages and the site as a whole. what i need to know is this in a kind of yes or no fashion: will php allow me to create a class and then have access to the class from other pages and scripts ? Steve