How do I post a spreadsheet?

What about the Graph part though?

IN short you can't these groups are text only discussion groups. You could put it on a file download site and post a link.

No-one in their right mind will open a XLS* or DOC* file of unknown provenance so your best bet is save all the numeric content as tab delimited and include some notes on what to plot to see the graph.

You could provide instructions as to what area to select for plotting.

There is quite an art in saving formulae so that a spreadsheet in tab delimited text form can be downloaded inspected and then loaded into Excel to work dynamically on any new data.

Post it to your website if you have one

Thanks everyone for your useful input.