EPThttp://pogue.blogs.nytimes.com/2008/06/12/how-to-block-cellphone-spam/
Other than trying this stuff there is also the 'National Do Not Call Registry' which covers cell phones as well as land lines:
https://www.donotcall.gov/
I am not sure but I think they also have a feature in the works for the text spam coming soon (if not already).
Also, http://www.fonefinder.net/ is pretty cool for tracking phone numbers by location. Sort of like a reverse phone book.
This too http://www.whitepages.com/reverse-lookup
