I met the founder of Mozes at Mashup Camp earlier this year.
They just rolled out the beta version of their new service. To use Mozes, you simply send (or "text" as my kids would say) an SMS message to 66937. The message must start with the word "book", a space, and then the 10-digit ISBN number. Mozes will return a mesage with the book's title and the average customer rating, all powered by ECS.
But Mozes does a whole lot more than this. Have you ever wanted to know the name of the song that you just heard on the radio? Text the radio station's call letters (e.g. "kfog") to Mozes and it will tell you!