UС3524 UС3825 are not flyback circuits. UC3842-UC3845, TDA4605 are what you need. They're properly discribed in the datasheets. General information about flyback operation can be found in SMPS books (download here).
Btw. why not to use something integrated? TOPSwitsch for example ?
I din´t suggest TOP switch cos U asked abt UCnnnn IC´s but if U are able to get TOP parts visit www.powerint.com there U will find very good apps notes, PCB layouts and also a soft that will fast your design.