In SQL Server 2005, and the non-Enterprise editions of SQL 2008/SQL 2008 R2, SSIS doesn't provide an out-of-the-box option for bulk loading Oracle data. Instead, SSIS components implement single row inserts to load data to Oracle. This can result in issues such as long load times and timeout during the ETL process.
This article on MSDN provides alternatives for achieving optimal performance when loading Oracle data, including instructions and code example for a customized script component.
Optimized Bulk Loading of Data into Oracle
The article has been updated to apply to SQL Server 2012, as well as SQL 2008 R2, 2008, and 2005. As before, the article is located at msdn.microsoft.com/.../hh923024.aspx