I have used this chip...and in my opinion it is not EZ (easy) at all.
You might be thinking of the firmware which is in ROM on the chip itself. (And therefore cannot be written or modified) This is the code that contains al the low level USB drivers. You <i>can</i> get the listing for this if Cypress are feeling generous, but it is only useful for unravelling the obscure bugs that this chip is particularly good at generating.
If you are thinking of the USB application code that goes above this, the development kit contains a beginners guide (book) to installing, using and editing the application code, with explicit instructions on how to build and download your code to RAM or EEPROM. This step by step guide should be the first thing you do with your development kit.
If this is a new project, I would ask Cypress to recommend an alternative IC.
by the way, this is an EZ-host, not a PSoC.