Do you use Yahoo email on the phone? Yahoo IM? Do you use OZ instant messenger?
Most likley it is yahoo mail. In any case, you can login to your Sprint page and block them.
See this post for more info:
http://www.sprintusers.com/forum/sho...=139228&page=2
"It's a problem with Sprint Mobile email application that comes with most phones. It's actually quite helpful since it will allow you to get push email (ie instant email or blackberry like email) straight to your phone. The problem is if you uninstall the program or stop using the program without resetting your email information on the server, it will keep sending the email (push) notification in the form of the 9114 text message gibberish. I have the Touch and found out through trial an error and noticing that the texts come at the same time I kept getting emails.
A more decisive fix instead of just blocking the text message sender is by using the Sprint email program and re-enter your infomation for your previous email account. If you don't remember just start sending emails to your various email accounts (allow a few minutes between each) and wait to see if you get a text from 9114. When you find out which email it is, you should register with that same account again.
Once you have done that select re-register under the menu. Don't enter anything after that. It will clear your info off the server and now you can uninstall the email program AND you will stop getting the texts.
So in short, don't blame the gmail or yahoo, it's not their fault. The program is really to blame although it's a symptom of push email which is nice to have for free."