This requires bitpim but is much safer than the traditional way. It also requires a memory card and a way to plug the card into the computer like a card reader. MEK won't work.
1. Download the damn thing
(select your phone...there is no a990 so you have to click a930 and have the port "manually set". you will see all those options when you go through the phone setup)
2. go to phone > media >ringers (click image below for example)
untitled.jpg
3.click the music note with the green plus(add ringer)button. Make sure the song clip you want to add is easy to find by placing a copy on your desktop. You can place a full song as a ringtone but it takes up way to much space and time to transfer so cut the song up sorter using any one of the billions of programs available to do that.
4. this will launch something that says convert audio file. unless you want to play with the setting just click convert. when the dos screen is done click ok. It will probably say file is too big do you wish to continue. select yes because we aren't going to place it in the phone like normal bitpim users.
5. Put your memory card into your computer and right click the start menu, then click explore. find the removable drive which relates to the memory card and you should see 4 folders (my pix, flix, sounds, music). Go to song you just converted in bitpim and right click it. Select "copy". Go to "MY Sounds" folder on your memory card and paste the song in the folder.
6. The super sneaky step. The phones have mp3 as ringtone blocked so what you have to do is rename the song to a .mid . for example if you picked buckcherry.mp3 you have to manually change the file name to buckcherry.mid The computer will give you a warning stating "changing file name may make file unreadable" select continue and just manually rename all of your bitpim mp3's to .mid
Put the card back in your phone and you are done. You can't take mp3's straight from your p2p programs and put them on your card to make them work you have to run it through the bitpim first. Although it is only confirmed on the a990, I am sure it will work on any phone with a memory card. Good luck.