Futuresource.com , type in a symbol on the left (lets choose C) Brings up the futures chain, click on the first icon next to any month (the icon looks like a chart) To chart May '08 - May '09, type in ='C K8' - 'C K9' See attached pic. (its a crude oil spread chart, the only thing I already had saved)
Try the internet.....type in your keywords into a search engine. If you don't know what a search engine is please start a new thread about where to find search engines.
I subscribe to this service for other spread charts and some neat tools, but I believe corn is free: www.scarrtrading.com E
Is this what you are looking for? I am trying to post an image but it is not showing up in preview or attached. http://bp2.blogger.com/_9OvXYQXlabc/SC04XV_y6yI/AAAAAAAAAYI/L4f9mfTm5zw/s1600-h/Corn.jpg http://bp0.blogger.com/_9OvXYQXlabc/SC07J1_y6zI/AAAAAAAAAYQ/-HYACsyaw94/s1600-h/corns.jpg