Yes. Go to twitter.com and login. Click on "Following". One at a time, click on the names of the people you're following. For each one, look in the right-hand pane for the cell phone symbol next to the green "Following" button. If the cell phone symbol is green/white, then you're receiving a text whenever that person tweets. Click on the phone symbol and it will turn white/gray. That turns off the texts, but you'll still be following them and can still see their tweets in Twitter apps on your phone, which uses data and not text messages to get updates.