Hi all,
I'm new to crackberry.com and new to owning a Blackberry as well.
I agree with rlem00 about Audacity. It's freeware and overall a *very* powerful program. They've got a big user community out there, as well as several guides. I've used it here and there and when I have I found it easy to work with and got the results I wanted the first time =).
That lil commercial out of the way, I found a great article on cnet.com that's a bit more for intermediate users of this program, but is well written so it should help the novies too =). Besides cleaning up the sound of mp3's in general, it also gives a brief how-to on making your own ringtones (towards the end of the article).
To get there follow these steps (the forum wont' let me post URL's until I've hit 10 posts

)
1. Go to cnet dot com
2. In the search field, type:
Audacity, ringtones
3. The article you're looking for is called:
"Becoming an MP3 Master with Audacity July 11, 2007"
I was concerned that the article didn't address the better capabilities of the blackberry so I d/l'd Nightrider as well as the Super Mario Bros. theme at tuneusin dot com and found that it used these values:
ringtone duration: 17/21 seconds
bitrate: 80kbps
channels: 2 (stereo)
audio sample rate: 32khz
(with exception to the duration everything was the same)
I think it's somewhat odd that the creator of these ringtones would keep it as stereo. I didn't think Blackberries had more than one speaker. That said, you might be able to save more space (while not sacrificing audio quality) if you make your ringtone mono. I'll experiement with this and let you know how it goes =).
Hope this helps!
Thanks,
JFresh