Here are some references-
You may want to refer the post /forums/p/21189/1306651.aspx This has flyback transformer subcircuit model, which can be readily used. You need to tailor the parameters as per your design.
You can also refer EDAboard post - http://www.edaboard.com/thread274918.html for basic simulation model.
TI App note http://www.ti.com/lit/an/slva589/slva589.pdf