Using cellphone and other mobile devices to implement teaching

I think mob devices can be very helpful. Has anybody succes stories using them?

I've found a nice link:
http://mlearnopedia.com/component/option,com_news_portal/Itemid,152/

does anybody know of a free web service that allows to send SMS to several phones (I live in Italy, so what works in the USA may not be available here!): any help appreciated!