lpc21xx tutorial
it is so easy
u can program the chip using a simple serial connection to ur PC
using linux, there is a complete toolchain for compiling, debuging and programming the device
it really does not need any special tutorial
u just connect the suitable chip's pin to ground, and connect the serial port of the LPC device to PC using a Serial-USB cable ( like what FDTI produces ) finally u run a simple program at PC side
I'm talking all about linux, there a program called lpc21isp will get ur compiled elf and will program it into ur chip, when finished, disconnect the programming pin from ground.
I know that it is also possible to program the device directly with USB, but we never used that technique. We are currently using LPC2148 device widely in out projects
good luck