This can be done even easier.
A new version of scriptlogic's enterprise secuirty reporter 3.6 (beta version is available at http://wwww.scriptlogic.com/beta) is a good answer to sql server security reporting needs.
The solution includes a very powerful discovering and reporting engine with built-in ready-made and custom reports including reports on database object and schema permissions, effective database object permissions, database users and role membership, server logins and server role membership.
The tool supports all popular SQL Server versions like SQL Server 2000 and 2005 as well as MSDE and SQL 2005 Express.