What works for me...
I download clips from
www.myxer.com. When they are downloaded, I then install them straight to my storage card (no folder,etc)... uncopyrighted and in mp3, .wav; any various format.
From the storage card, my Sounds & Notifications menu automatically recogizes everything on my storage card. No hacks or reg edits. If I set a mp3 song for a text alert it will play the entire song when I recieve a text message unless I cancel the song or pre-clipped to 30 secs.
Myxer has many clipped tones & songs for mobile devices that are ready for instant download and even straight to your phone. You may have to initialize a setting on your phone to get your storage card recognized. Otherwise you may have to drop them into the \windows dir but like I said... they are automatically found on my storage card.