SQL2K5 D/B Schemas

1) Can anybody recommend any good articles/tutorials for creating D/B schemas for a SQL2K5 database?

2) Any suggestions on the best way to secure the database by breaking up access into the following roles (NB discountasp.net allows 3 additional D/B users):-

a) an anonymous visitor with mostly read access to a restricted set of tables

b) a logged in user, with additional insert/modify access on a broader set of tables

c) a webmaster user that performs day-to-day D/B admin, through admin web pages, i.e. requires insert/modify (row) access, for all the tables, but with limited delete (row) access and no create/delete/modify access for table and other objects.

d) keep the dbo (default) user for infrequent, remote database house-keeping functions and D/B updates.

Users (a), (b) and (c) login credentials would be stored in the web.config file, and (d) would only be used remotely.

3) On second thoughts, would it be better to only allow access to the D/B through stored procedures, which would be simpler to break down into the above users than on a table-by-table basis? Then only allow stored procedures, and other objects, to be created/modified/deleted by the dbo (default) user.

Any advice/suggestions would be greatly appreciated!