I just this phone this week through Alltel and bought a 4gb micro card for it, unfortunately you can not take a ringtone and add it directly to you phone using the card. The only thing I think you can use the mirco card for is playing MP3 music. I know this is true for Alltel and Sprint because they have a block due to what they say is to prevent "illegal" music upload issues. My thought on that is its just another way to make money
Anyways, I was tinkering with the phone last night and successfully added ringtones to my phone using a USB Plug and BitPim. Here is what I did:
Open up BitPim and click on view. Make sure there is a check next to "View Filesystem." If not, click on it to check it. Then, plug in the phone. It will say "Other CDMA Phone on _________."
On the left hand side of BitPim, expand the folder Filesystem. Then click on dload and right click on "lg_mysound.dat" and back it up to your computer. Once you have backed the file up, delete it.
Now expand the folder brew and media and lk and finally click on ms. Then, open up the folder on your computer with your ringtone files, and drag them into the ms folder in BitPim. It will take about 30 seconds or so to add each file.
Once you have added all of your ringtones, unplug the phone from your computer and reboot your phone.
If you need help finding BitPim or Drivers for your USB here's where I found them:
If you still having problems I can help walk you through them.