Installing the kext file can be done in a few easy steps:
download and extract
$ cd /path/to/osx-pl2303.kext
$ sudo cp -R osx-pl2303.kext /System/Library/Extensions/
next you need to fix permissions and execute bits:
$ cd /System/Library/Extensions
$ sudo chmod -R 755 osx-pl2303.kext
$ sudo chown -R root:wheel osx-pl2303.kext
load the module and update kernel boot caches
$ cd /System/Library/Extensions
$ sudo kextload ./osx-pl2303.kext
$ sudo kextcache -system-cache
For deinstallation, perform these steps:
$ sudo rm -rf /System/Library/Extensions/osx-pl2303.kext
$ sudo kextcache -system-cache
Driver Link:
http://www.xbsd.nl/pub/osx-pl2303.kext.tgz
Credit to : xbsd.nl (http://www.xbsd.nl/2011/07/pl2303-serial-usb-on-osx-lion.html )
