ringtones

You click on the link I provided above, download the program and install it on your phone.  I have not used MiniTones myself so I can't take you farther than that, though I would expect the web page I linked to have instructions on use.

You do not need Mintones or other apps to do this. Here's how to add it to your tones library:

Make sure your device is updated to the most current revision of PalmOS (There have been updates since the release of the Centro), and then use Ringo Pro, Mim, or other ringtone managers. You can also add MP3 ringtones into your device by following these instructions:

• Place the MP3s file you want to import in the Audio folder of your (micro)SD card.
• In the Blazer web browser, type: file:///audio/xxx.mp3 where xxx is the name of your mp3 file, note 3 forward slashes after the file.
• Hit GO.
• Then you will be prompted and select Copy To Ringtone.
• Then Hit Save and Open.
• The MP3 Ringtone will now be added to your Ringtones which you can Manage from your Prefs/Sounds.

In addition to mp3's the latest Palm smartphones support a number of ringtone formats including: AAC, AAC+, MIDI, WAV, and AMR.

The 3rd party apps add additional functionality to the Centro or Treo, but aren't needed to actually use the tone itself.