Okay, I finally finally finally, through searching and searching found a legit website that will send an sms to any cell phone without knowledge of carrier. My friend at Sprint PCS actually told me about it. The cell phone can even answer back, and it's completely free unlike most of those sites that will do the same thing.

cellphonenumber@teleflip.com

It works with all North American carriers. If you have questions just go to:
www.teleflip.com

I have no affiliation with this website...I'm just so excited to have finally found it. Apparently it's been around for quite a while.

-Brian in Kansas City