was looking at a friend of mine photos on flickr and found this little tid bit
it showed his email to address from his nextel phone ... along with his phone number of his nextel as the send from address
and to confirm this do a search on flickr with "messaging.nextel.com" and it will show you the phone number of the nextel user along with the "Secret Email Address" to send photos to flickr
vtext.com also turns up a few...
and tmomail.net
check it out kewl stuff