This is a driver for the many-and-various Prolific PL2303 serial-to-USB
adapters that are out there.  I didn't write it, nor did I even update
it to work on Snow Leopard -- I just had the occasion one day to be
standing in a datacenter in front of a router needing to be consoled and
an old PL2303 adapter in my bag... wanting a nice binary package of a
driver that worked.  This driver (once patched) works great under Snow
Leopard, but otherwise seemed unmaintained.  Forking and moving to
GitHub was probably an extreme measure, and probably not the best for my
open-source karma (whatever that is), but it was the shortest path to
getting a working DMG into your hands, so you take the good with the
bad, I guess.

That said, if you want to cut to the chase and grab the driver, a nice
readymade PKG is here:
http://github.com/downloads/failberg/osx-pl2303/osx-pl2303-0.4.1-failberg.pkg

I'm happy to accept additional patches onto this - feel free to fork and
send a pull request and I'll try to get new builds done in a relatively
timely fashion.

If you need to add additional device IDs or vendor IDs, those live in
Info.plist; just clone the relevant section of the plist XML and create
a new stanza - and be sure to send me a patch!

Thank you to B.J. Arnoldus for writing the driver in the first place,
Michael Haller for patching the driver to work under SL, and the various
folks who contributed patches to the Sourceforge tracker, some of which
I've applied here.

-Bryan