Hallo Maddy,
you'll find the owners of schemata with the following query:
SELECT s.name,
p.name
FROM sys.schemas s INNER JOIN sys.database_principals p
ON (s.principal_id = p.principal_id)
Before you can drop a database user you have to drop the owned schema or change the owner of the schema
ALTER AUTHORIZATION ON SCHEMA::SchemaName TO NewOwner
Get more details for authorization here:
http://msdn.microsoft.com/en-us/library/ms187359.aspx
Uwe Ricken
MCITP Database Administrator 2005
MCITP Database Administrator 2008
MCITP Microsoft SQL Server 2008, Database Development
db Berater GmbH
http://www-db-berater.de