Help! Need to send text to more than 250 contacts.

If your phone has a limit of 250 people, that's what you have to work with. Mass text messages aren't exactly reliable either, and some networks will actually cut off your text messaging if they see a huge flood going out.

Try a social network instead. (Twitter, Facebook, Google +)

 

Another option (assuming you use Google to sync contacts) would be to go in to your Google account and split that list of 300 into probably 10 groups of 30 and then send the mass texts to those 10 groups one group at a time. That should break it up sufficiently to avoid the flooding issue. Much easier to maneuver contacts and organize groups like that on a computer on your Google account. Should take all of 5 minutes.