Well I know how to send it by Verizon.
With Verizon if you put your number + area code (no spaces or "-" in between the numbers) and then add this at the end @vzwpix.com then attach your ringtone in the email and send.
Now for a different company try sending something from your phone to your email and with the address that came from your phone keep it because if you save it then you can use it to send things to your phone, like photos, ringtones, videos, ect.
if you don't know how to send things to your email by your phone all you have to do is go to your text messages, make a new message and in the address instead of numbers for a phone number all you have to do is write in your email address (sorry if you knew this already, some people don't know how to do this step)
I hoped this helped you.
Well, I have Verizon and this sounds great except I'll be damned if I can find a way to attach the file. If i try sending it to my email, all it does is send a link for the song on this site. Great!