TextSanity

The TextSanity plugin is a plugin that allows WordPress users to connect to their TextSanity account. The plugin creates an admin section where you can add, modify, and control forms where visitors to your website can add their phone number.

A plugin that integrates TextSanity with WordPress.

gvilabs

This plugin makes a function available to allow WordPress developers to send an sms/text message to whichever phone 
number they want.
Usage of this plugin requires signing up and registering for a paid-for account with <a href="http://www.grapevinedirect.co.za/" rel="nofollow ugc">Grapevine Interactive</a>.
This is a service plugin only, it does not do anything by itself, it just makes the smsing/texting functionality available 
for developers to call at appropriate times.
<h3>Usage in code</h3>
As an example, use the following code wherever you want an sms/text message to be sent:
<pre><code><?php if (function_exists("za_co_vine_sms_sendSms")) {
 za_co_vine_sms_sendSms("0821234567","message content here");
} ?>
</code></pre>
Try to use this code close to the end of the WordPress Loop execution, as the function will block while doing the HTTP post.

Grapevine Interactive SMS Plugin

SMS-enable Wordpress. Makes a function available to allow sending of sms/text messages from within the code. Requires registration and payment.

TextSanity vs Grapevine Interactive SMS Plugin