I assume you are backing up your production database, correct? Just copy the latest full backup to the development server.

If you are replacing the databases on the Dev server with updated data from production, then you RESTORE them with the same name, using the WITH REPLACE syntax (http://msdn.microsoft.com/en-us/library/ms178615.aspx)

If the file paths are different on Dev from production, you need the WITH MOVE syntax.

Typically you have different logins/users on DEV than production. If they are the same, the logins need to be on the Dev box. If they aren't, sp_rev_helplogin from MS will help you move them.

To sync back up users with logins, sp_change_users_login (http://msdn.microsoft.com/en-us/library/ms175475.aspx)