what is the first schema checked?
With SQL Server 2005 &amp; 2008 the first schema that is searched is the users default schema.
from SQL Server Best Practices – Implementation of Database Object Schemas

Default Schema
Users can be defined with a default
schema. The default schema is the
first schema that is searched when it
resolves the names of objects it
references.

and

creating the base tables in
the dbo schema will enable table
objects to be referred to without an
explicit schema name. This is because
an object will be located by searching
the default schema first, followed by
the dbo schema. So:
SELECT * FROM Table1
Will assess the following statement first:
SELECT * FROM &lt;defaultschema&gt;.Table1
If it cannot find the object, the server will assess the following statement:
SELECT * FROM dbo.Table1
The assessment process can be improved by using either the fully qualified name
or the DEFAULT_SCHEMA option described earlier. By setting a value for
DEFAULT_SCHEMA for the user, the server will check the DEFAULT_SCHEMA
first, removing an unnecessary ownership checking process.
This can improve performance considerably on heavily utilized systems.

Default Schema was introduced in SQL Server 2005 Upgrading to SQL Server 2005 and DEFAULT_SCHEMA setting