Found this info on an android forum, though ti might be useful.
For CALLER ringtones you may already know that creating a "rintone" folder on the SD card (and filling it with MP3s) will show up in your ringtone list.
But for MMS SMS and EMail Notifications,the mp3s in the ringtone folder wont show up.
Create a folder on your SD card called "notifiations" and it will do the same for your mms sms and email ringtone list!
UPDATE!!!!!!!!!!!!!!!!!!!!!!!! NEW file structure that will let you do the above ASWELL as add alarms!
On your SD card Create the following file structure:
Media (in root of SD card)
----- Audio (in the Media folder)
--------- Ringtones (in Audio folder)
--------- Notifications (in Audio folder)
--------- Alarms (in Audio folder)
Now just Drag n Drop your favs into the folder where you will be using it, or ALL of them (like i do) and they will appear in the default lists. No app required !!!
Dont worry, you can still use "DROOOID" (i do!! )... but you have unlimited others to add now!