The US text messaging plans are cheap compared to the rest of the world. You need to sign up for a bundle. Some charge you to receieve text messages, some dont.
There is a great tool, which allows you to send a text messages to 2.3 BILLION phones. there are only 5 million black berry users - do the math. Anyways, it sits in Microsoft Outlooks ..check it out
Red Oxygen - Email SMS, Outlook SMS, Email Text, PC to SMS