IT'S EASY TO DO:
Just login to your Tunebubble account. (top left of homepage)
YOU CAN NOW ADD AUDIO FILES TO YOUR PROFILE, so make sure you add your new song to your profile first. (These play in a music player, no-one can download them)
You will see 'Submit a Tweet' in the dropdown menu
Just fill in your Tweet, include your Twitter tag, so people can find you, add your link and submit, we'll do the rest!