We'll eventually be adding clickable column headers so that users can choose what sort order they'd like, but it hasn't been a priority yet. (Requests for features in the forums do play into our prioritizations, though.) In the meantime, hard-coding ORDER BY clauses into classes/user/UserDAO.inc.php is the best approach.
The getUsersByRoleID and getUsersByJournalID functions appear in RoleDAO simply because they reference the roles table in addition to the users table; an argument could be made for these functions to be placed in either DAO. It might be conceptually clearer e.g. to have all functions returning Users moved into the UserDAO, in which case we might move these functions over at some point during a code review and cleanup.
Public Knowledge Project Team
Don't miss the First International PKP Scholarly Publishing Conference
July 11 - 13, 2007, Vancouver, BC, Canada