Got it!
Alright. First off, download the proper driver:
http://www.viewcon.net/driver/rs11/imac.sit
Second, install it.
Third, don't reboot. You need to edit the Info.plist for this driver.
Code:
tibox:/System/Library/Extensions/ProlificUsbSerial.kext/Contents root# ls
Info.plist MacOS PkgInfo Resources pbdevelopment.plist
open up Info.plist in your favorite editor (yay vi) and add the following to the <dict> section:
Code:
<key>067B_AAA0</key>
<dict>
<key>CFBundleIdentifier</key>
<string>com.prolific.driver.PL2303</string>
<key>IOClass</key>
<string>com_prolific_driver_PL2303</string>
<key>IOProviderClass</key>
<string>IOUSBInterface</string>
<key>bConfigurationValue</key>
<integer>1</integer>
<key>bInterfaceNumber</key>
<integer>0</integer>
<key>idProduct</key>
<integer>43680</integer>
<key>idVendor</key>
<integer>1659</integer>
</dict>
Reboot, open up kismac/terrabrowser/whatever and tell it your GPS is at /dev/tty.usbserial0
Tada!