Download and install the LG Driver.
Download the newest version of BitPim (1.0.6).
On your phone set PC Connection to USB MODEM.
Connect the phone to the computer using the USB cable.
Run BitPim.
Let it find the phone(it will come up as other CDMA phone)

Click FILESYSTEM on the left at the bottom (If you don't see it then click the View\View FileSystem menu).
Double click Filesystem folder.
Double click Dload folder.
Right click lg_mysound.dat and save it to a local PC folder e.g. c:\Temp.
After you save it right click lg_mysound.dat and delete it (if you have problems deleting it then click on the Find Phone icon and try again).

Open the brew folder.
Open the media folder.
Open the lk folder.
Open the ms folder.
Now drop the songs you want to use as ringers in the ms folder (they will automatically load into your phone. It is not the fastest process but it works).
When done loading, unhook USB cable from computer, power the phone off and then back on.
The songs you just transferred will now be in the my audio file where they need to be to be assigned as individual ringers.
NOTE:
Everytime you whant to add new ringers to the phone you have to complete all the steps above, even the deleting of the lg_mysound.dat file.
Good Luck, Marco
BitPim screen-shot: