Userids/logins And Permissions?

Hello:

We are working on an application but with other users who have been using the SA password. The application is running on MSSQL 6.5 and sp4.
We have been generally assigning logins/userids to new users although some people are using the SA id. The SA id password has been changed so that will stop users (really developers) from using it.

Most users are assigned to a group which has select, insert, update, delete
permission. Some users will be moved to a group which as only select privilege

I would like to query the system tables and see exactly what permissions
are assigned to each user.

I can look at Enterprise manager and cut and paste this information I think.This is cumbersome

1) Does anyone have a query I can run to get the userid/login and the permissions for each userid?

2) How can I make a user a dbo and give him/her the same permissions as a dbo on tablesalready creaetd?

Thanks.

David Spaisman