OK, I've uploaded a new release. Special thanks to Rudolf for suggesting some changes to me

Changes:
- On installation, mark all members as having read the agreement
- When a new user registers, do not prompt them to agree (as they already did during registration)
- Fixed minor error reported by
RoarinRow - Instead of checking last modified date of changelog.txt, a setting has been added to the admin panel to mark the agreement as changed
- Moved code from index.php to loadUserSettings function in Load.php
- The install script checks to see if the column already exists
You'll need to
uninstall version 0.1 before installing 1.0 (the latest one)
Edit: Clarified changelog