I should have added that the clips should be 176 x 144, the standard video size for mobiles.
You can email direct from your phone to firstname.lastname@example.org
or use the online uploader at http://www.15x15.org
Also the clips dont have to be exactly 15 seconds long as we will batch convert, and so reduce each clip to 15 seconds. Max file size is 2MB though.
You can also send as many clips as you wish!