TrueText

is a simple program to block the unwanted SMSs which contain the specific word.The SMSs which contain the content in Blocked Content will not appear in the SMS Inbox. However it can display the lasted 25 text messages in TrueText, so you can still read them in the program.
Useage
You can add the content(case sensitive) such as word to the blocked contents, then TrueText will block them automatically.
Limitation
If you are using other SMS software which will receiving new incoming SMS, then it may conflict with TrueText and make TrueText can't block all incoming SMS

Download
http://appworld.blackberry.com/webstore/content/54761?lang=en