There isn't help with the Flex API and Oracle SDE. What exactly do you need help with? If you need help setting up ArcGIS Server to use Oracle SDE connections for your services, I'd suggest looking at the ArcGIS Server help.
If you are looking to connect Flex with your Oracle database to perform SQL queries, you need to set up a backend script (PHP, BlazeDS, etc). There is plenty of help articles on Adobe's site.