interface USB Keyboard to 8051 Microprocessor

we would like to interface USB Keyboard to 8051 Microprocessor like AT89X52 or N79E352RADG, we already have our project up and running on a PS2 Keyboard, we are ready to change the Microprocessor but it has to be 8051. we need expert advice on which components to use from some one who has already done something like this. would like to start with hourly charges.