Connect to Oracle stored procedure from SQL Server stored procedure...and vice versa.

I have a requirement to execute an Oracle procedure from within an SQL Server procedure and vice versa.

How do I do that? Articles, code samples, etc?

Oops, the actual requirement is just to query Oracle tables from SQL Server and to query SQL Server tables from Oracle.

Setting up a linked server in SQL Server accomplishes the first and is well documented in Books Online.

The second involves using Oracle Heterogenous Services or Transparent Gateway. I have not found very good documentation about how to use those.