Please refer to the following info about the drivers.

[Root]

Driver for Windows operating system: 

PL-2303 Driver Installer    PL-2303 Vista Driver Installer


[Folder]

WinCE:  Driver for WIN CE
Win98_ME: Driver remover for Win98, WIN ME
Win2K_XP: Driver remover for Win 2K, Win XP
mac:    Driver for MAC
linux: Driver for Linux, some useful tips for the driver