For all of you out there that think open source should be open source and get annoyed when a free plug-in becomes a free SEO plug for the original developer. I mean, SERIOUSLY I've never seen so much self-promotional crap all over a plugin IN MY LIFE. If it's not enough that your user interface has virtually NO CSS to make your forms line up correctly, you make all end-users visit your shitty looking website for more information. Dude, save your link spamming for the back-end.
The reason you can't find the commercial links in the source code is because that part of the HTML is encrypted. If you open sms-text-message.php, you'll see a large string of code after this:
All it is is the select close tag and the input submit button. If you take a good look you can probably figure it out without having to run it through a decoder.
If you're stuck, you can always copy the long string and run it through this decrypter: http://josh.thespiffylife.com/decrypt.php