jchristman2002,
This is straight from the Help document [F1].
"When Meet-Me Conferencing is enabled, users have the ability to initiate or join a Meet-Me Conference by dialing the Conference Assistant and entering a valid access code. Access codes are generated to match each “User” main extension number in the system (as programmed in the Users folder), so that each designated “User” (not phone) has their own access code for establishing conferences.
In addition to the personal access codes that match each “User” main extension (as programmed in the Users folder), the User Web Portal application and the updated Configuration Assistant application can also be used to create unique system-generated access codes".
Now, with that being said you can manually create a user that doesn't have a Main extension associated with it, which is where it gets its password from, and it then would have no password; in theory. I have not tried this as I find the idea to be an "odd" one that would allow users to enter in to a conference on accident or on purpose that others may or may not be in.
Thanks,
TE