So far the solution is to buy DRM-free music files.

You can always download MP3 music files from say eMusic, then trim them with a free software like MP3DirectCut and transfer them to your mobile phone.

You may also choose content providers that provide DRM-free ringtones. In many cases you will pay the same or comparable price compared to the tunes bought in a music download service so probably there is no sense to do that.