Hi,
the serial programming algorithm (ISP) for the LPC932 is no secret at all.
You'll find the serial programming algorithm in the Datasheet or in the Users Manual.
They just can't give you the parallel programming algorithms.

Just because I'm interested, why do you want to write your own
programming Software?
You can buy parallel programmers for the LPC932 for an apple and an egg.
In your case (serial ISP programming) it is completely for free. The Software (FlashMagic) can be downloaded from ESAcademy.com and the hardware interface is not more than a RS232 interface.
Good luck,
Christian