Please enter the long/lat area and press the button ( Get Tiles ) to get all the Tiles names of every Zoom level used in OpenStreetMap.
At the same time you get a link to the Bigmap
To get the long/lat values you can use the export tab on openstreetmap.org
To obtain the long/lat just fill in the values X,Y and the zoom, press ( Get lon/lat ) and you havee the result in the lon/lat fields.