Create Ringtone Mobile is a Windows Mobile Pro (Pocket PC) application for touch-screen devices. This app will let you create and edit your own ringtone directly on your phone.
Features include a melody bar-graph to divide the song, WAV/MP3 support, size adjusrment, support for storage cards and a friendly interface.
Try or buy the program here for $19.95 (around £9.74)
Link – Create Ringtone Mobile