The LPC214x controller offers USB and UART interfaces. For a start it's
much easier to use the LPC's UART. If you PC does not offer a
serial-port you can use a usb-serial cable available in nearly every
You need an interface-IC like i.e. a MAX3232 between LPC and PC's
serial-port. Just look into the schematics of LPC214x evaluation boards
Example-code on reading from/writing to an LPC UART can be found in the
net (i.e. in the sample-collection fro LPC213x/214x from NXP.com,
example-code from Bill Knight in the LPC yahoo-group).
Once you are familiar with developing code for the LPC you can start
using the LPC's USB-interface.