Free service to test sms sending to US mobile

I've just needed to test integration with ExactTarget service which sends sms just to US customers of our website.

I've tried couple of websites with fake US numbers (like http://ift.tt/1w0L5me etc.), registered twilio account and got free trial phone number, but in all these cases sent sms is not displayed anywhere.

In case if we use the real US mobile number, sms is sent correctly. So the problem is not in our business logic.

Could you please, guys, recommend some good free services (live now) to receive sms online on US mobile phone ?

Thanks in advance for your help