If it's pre-programmed, you just need the right description of the chip in your Arduino IDE's "boards.txt" file. That file should be found in your Arduino installation directory.
There are a couple of different "pre-programmed 328" vendors, and they may have different versions of the bootloader. Everything should work fine for either version, but the settings in boards.txt may depend on which vendor sold your chip. As of this writing, the 328 stuff is all very "bleeding edge" and subject to changes as such variations become standardized.
Usually, switching platforms should be done one step at a time, to ensure you know the implications of each switch. Getting a new OS, new board system, and a new chip for the board system, all at once, well that's either daring or... well, daring. 