I found MP3's always sounded crappy and too quiet on the 220 so I editied one and it's not too hard. You need an audio editing tool such as Goldwave. Here's what you do.
-Trim the song so that it starts at a good loud point, most songs are too quiet at the beginning. And you don't need the whole thing, especially if your answering service kicks in after a few rings...
-Use an equalizer tool to remove any sounds lower that 100hz since the speaker on our phone can't handle the bass anyways...
#This will remove distortion for when we make it louder.
-Use a compression tool to trim the whole song to a hard limit of 6db's
#This trims off the high volume peaks that will distort. It smooths it out.
-Increase the volume 150-200%
#Sometimes it take a couple tries to get it as loud as possible without distorting, but the 2 previous steps really help removing distortion and letting you max it out.
-Save as a wma file in mono at about 48KB/s bitrate, or to your preference here. WMA files are louder than MP3's for some reason.
Upload to your phone!
Here's one that I did (attached), try it in your phone, it's nice and loud. I'm still tweaking to make it sound as good a possible while still being loud as possible... It may not be your kind of tune but this will of course work well with any song...
Hope this help, I'm making lots of ringtones now that I'm able to hear them!