book = Workbook('filename or filedescriptor') #Open xlsx file
for sheet in book:
    print sheet.name
    for row, cells in sheet.rows().iteritems(): # or sheet.cols()
        print row # prints row number
        for cell in cells:
            print cell.id, cell.value, cell.formula

# or you can access the sheets by their name:

some_sheet = book['some sheet name']
...