You can find a one of good services for free sms at www.openpost.de. OpenPost offers 10 sms with 137 characters (other 23 characters will be used for the link to openpost.de) monthly for free.
To be able to send free sms you must be registered at Openpost.de. The registration is very simple and fast.
P.S. I would like to say thanks to Steven for this tip.
