.adp, .ade, MSDE and Permissions

Hi,
I'm working on a project that will be accessed by 5 or 6 users. The database
is on a Server (Small Business Server 2003) and I've used MSDE for it. The
front end is a copy of the .adp (possible .ade when tests are finished) on
each user computer. Now I need to decide which method is better to set
permissions... I've read so much information and still can't come up with the
best solution. I don't want the users to have to login twice (SQL Server and
project). I have a login form that takes the UserName and Password (saved in
a "Users" table that includes the group they belong to). Once they pass the
log in, a main menu shows up with the different areas they can work in
depending on the user's permission (Admin, Data Entry, etc.) I'm thinking on
using VBA to set the groups and permissions so if the user belongs to the
Admin group (Owners of Company: they can add/change users and passwords, see
who is login, etc) Technicians group can work on certain area but read only
other areas, etc.
Users can't access the tables and queries, just forms and Reports. Is this
enough security? Is there a better way to do it? I don't want the owners to
mess with SQL commands and they want to be able to set users and passwords...
Can I work with the permissions on the forms or I need to do it on the SQL
Server Database?
I have remote access to the server to manipulate the database until is
finish, I don't want the Company to be depending on me or other administrator
to do the minor changes.

Any help or idea I would really appreciated. I'm pushing myself to start
using something else than .mdb databases and the learning curve is tough but
worth of trying.
Thanks
--
gaba