To compile programs for the C8051F320 or C8051F34A microcontroller, a compiler is needed. There are a couple of commercial ones, but the only good free C compiler seems to be the Small Device C Compiler (SDCC).
An IDE is not strictly neccessary, but there is a decent one for Windows available from SiLabs.
See page on Programming Microcontroller for more information.
Linux Driver for Programming Cable