Mac Users:

Try this out:

Check the thread at the top of this forum which discusses ringtones. In there is the format you need to convert your mp3's in order to play them on your phone. Then do a Google search for that file format and see which programs are available in a Mac format. The older version of Philips Mobile Tools works great, but is it Mac compatible? I'm just giving you an idea on how to go about solving your problem. There's a wealth of information here, and doing a Search is the easiest way to find things.