Arthurmarx, I'm not certain, but I would imagine that the 7230 is limited to midi format ringtones. So any midi ringtone should be usable. Try looking in the Blackberry Ringtones Downloads using your BB internet browser for midi tones. You may be limited though as the 7230 is an older device and only has 16 meg of memory. What version of the OS are you using?
Hope this helps