What do you think about Excel Spreadsheets? Is it useful? Would you use it in your classroom?

Well, I'd say it's useful, especcially for applications such as grade books and other calculations. However, seeing as I plan on teaching English, I don't really see much use for them in my classroom.

As a teacher, why do we use Spreadsheet? What is the advantage of a Spreadsheet over a calculator?

Well, the most obvious use for Spreadsheet is for keeping track of grades and averages. Since you can program Excel to do averages, automatic calculations, and various other things, I'd say that Excel is superior to a calculator.