SMS stands for "Short Message Service." You probably know SMS by its more popular term "text messaging." We allot you a certain amount of SMS credits based on your activity on WebRing. To answer your questions...
A. "Can they be used?" Yes!
B. "How can they be used?" From your My Account page, you register your cell phone. After that, all you have to do is click the "Send Text Message" link to send a text message.
For more details see this page: http://www.webring.com/h/smsfaq